diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 86e010df..b0251c75 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -1,8 +1,19 @@
 version: 2
 updates:
-- package-ecosystem: pip
+- package-ecosystem: "pip"
+  directory: "/requirements"
+  target-branch: "2.0.x"
+  versioning-strategy: "lockfile-only"
+  schedule:
+    interval: "monthly"
+    day: "monday"
+    time: "16:00"
+    timezone: "UTC"
+  open-pull-requests-limit: 99
+- package-ecosystem: "github-actions"
   directory: "/"
   schedule:
-    interval: monthly
-    time: "08:00"
-  open-pull-requests-limit: 99
+    interval: "monthly"
+    day: "monday"
+    time: "16:00"
+    timezone: "UTC"
diff --git a/.github/workflows/lock.yaml b/.github/workflows/lock.yaml
index 7128f382..b4f76338 100644
--- a/.github/workflows/lock.yaml
+++ b/.github/workflows/lock.yaml
@@ -8,8 +8,8 @@ jobs:
   lock:
     runs-on: ubuntu-latest
     steps:
-      - uses: dessant/lock-threads@v2
+      - uses: dessant/lock-threads@v3
         with:
           github-token: ${{ github.token }}
-          issue-lock-inactive-days: 14
-          pr-lock-inactive-days: 14
+          issue-inactive-days: 14
+          pr-inactive-days: 14
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 06338f6b..b121dd8e 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -24,14 +24,17 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - {name: Linux, python: '3.9', os: ubuntu-latest, tox: py39}
-          - {name: Windows, python: '3.9', os: windows-latest, tox: py39}
-          - {name: Mac, python: '3.9', os: macos-latest, tox: py39}
+          - {name: Linux, python: '3.10', os: ubuntu-latest, tox: py310}
+          - {name: Windows, python: '3.10', os: windows-latest, tox: py310}
+          - {name: Mac, python: '3.10', os: macos-latest, tox: py310}
+          - {name: '3.11-dev', python: '3.11-dev', os: ubuntu-latest, tox: py311}
+          - {name: '3.9', python: '3.9', os: ubuntu-latest, tox: py39}
           - {name: '3.8', python: '3.8', os: ubuntu-latest, tox: py38}
           - {name: '3.7', python: '3.7', os: ubuntu-latest, tox: py37}
-          - {name: '3.6', python: '3.6', os: ubuntu-latest, tox: py36}
-          - {name: 'PyPy', python: pypy3, os: ubuntu-latest, tox: pypy3}
-          - {name: Typing, python: '3.9', os: ubuntu-latest, tox: typing}
+          - {name: 'PyPy', python: 'pypy-3.7', os: ubuntu-latest, tox: pypy37}
+          - {name: 'Pallets Minimum Versions', python: '3.10', os: ubuntu-latest, tox: py-min}
+          - {name: 'Pallets Development Versions', python: '3.7', os: ubuntu-latest, tox: py-dev}
+          - {name: Typing, python: '3.10', os: ubuntu-latest, tox: typing}
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index d75f3c31..a039d330 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,31 +1,32 @@
 ci:
+  autoupdate_branch: "2.0.x"
   autoupdate_schedule: monthly
 repos:
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.15.0
+    rev: v2.29.1
     hooks:
       - id: pyupgrade
         args: ["--py36-plus"]
   - repo: https://github.com/asottile/reorder_python_imports
-    rev: v2.5.0
+    rev: v2.6.0
     hooks:
       - id: reorder-python-imports
         name: Reorder Python imports (src, tests)
         files: "^(?!examples/)"
         args: ["--application-directories", "src"]
   - repo: https://github.com/psf/black
-    rev: 21.5b1
+    rev: 21.12b0
     hooks:
       - id: black
   - repo: https://github.com/PyCQA/flake8
-    rev: 3.9.2
+    rev: 4.0.1
     hooks:
       - id: flake8
         additional_dependencies:
           - flake8-bugbear
           - flake8-implicit-str-concat
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v3.4.0
+    rev: v4.0.1
     hooks:
       - id: fix-byte-order-marker
       - id: trailing-whitespace
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 0c363636..346900b2 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -1,4 +1,8 @@
 version: 2
+build:
+  os: ubuntu-20.04
+  tools:
+    python: "3.10"
 python:
   install:
     - requirements: requirements/docs.txt
diff --git a/CHANGES.rst b/CHANGES.rst
index f4e0b5d0..a57a97d2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,19 +5,79 @@ Version 2.1.0
 
 Unreleased
 
--   Update Click dependency to >= 8.0.
+-   Drop support for Python 3.6. :pr:`4335`
+-   Update Click dependency to >= 8.0. :pr:`4008`
+-   Remove previously deprecated code. :pr:`4337`
+
+    -   The CLI does not pass ``script_info`` to app factory functions.
+    -   ``config.from_json`` is replaced by
+        ``config.from_file(name, load=json.load)``.
+    -   ``json`` functions no longer take an ``encoding`` parameter.
+    -   ``safe_join`` is removed, use ``werkzeug.utils.safe_join``
+        instead.
+    -   ``total_seconds`` is removed, use ``timedelta.total_seconds``
+        instead.
+    -   The same blueprint cannot be registered with the same name. Use
+        ``name=`` when registering to specify a unique name.
+
+-   Some parameters in ``send_file`` and ``send_from_directory`` were
+    renamed in 2.0. The deprecation period for the old names is extended
+    to 2.2. Be sure to test with deprecation warnings visible.
+
+    -   ``attachment_filename`` is renamed to ``download_name``.
+    -   ``cache_timeout`` is renamed to ``max_age``.
+    -   ``add_etags`` is renamed to ``etag``.
+    -   ``filename`` is renamed to ``path``.
+
+-   The ``RequestContext.g`` property is deprecated. Use ``g`` directly
+    or ``AppContext.g`` instead. :issue:`3898`
+-   ``copy_current_request_context`` can decorate async functions.
+    :pr:`4303`
+
+
+Version 2.0.3
+-------------
+
+Unreleased
+
+-   The test client's ``as_tuple`` parameter is deprecated and will be
+    removed in Werkzeug 2.1. It is now also deprecated in Flask, to be
+    removed in Flask 2.1, while remaining compatible with both in
+    2.0.x. Use ``response.request.environ`` instead. :pr:`4341`
+-   Fix type annotation for ``errorhandler`` decorator. :issue:`4295`
+-   Revert a change to the CLI that caused it to hide ``ImportError``
+    tracebacks when importing the application. :issue:`4307`
+-   ``app.json_encoder`` and ``json_decoder`` are only passed to
+    ``dumps`` and ``loads`` if they have custom behavior. This improves
+    performance, mainly on PyPy. :issue:`4349`
+-   Clearer error message when ``after_this_request`` is used outside a
+    request context. :issue:`4333`
 
 
 Version 2.0.2
 -------------
 
-Unreleased
+Released 2021-10-04
 
--   Fix type annotation for ``teardown_request``. :issue:`4093`
+-   Fix type annotation for ``teardown_*`` methods. :issue:`4093`
 -   Fix type annotation for ``before_request`` and ``before_app_request``
     decorators. :issue:`4104`
 -   Fixed the issue where typing requires template global
     decorators to accept functions with no arguments. :issue:`4098`
+-   Support View and MethodView instances with async handlers. :issue:`4112`
+-   Enhance typing of ``app.errorhandler`` decorator. :issue:`4095`
+-   Fix registering a blueprint twice with differing names. :issue:`4124`
+-   Fix the type of ``static_folder`` to accept ``pathlib.Path``.
+    :issue:`4150`
+-   ``jsonify`` handles ``decimal.Decimal`` by encoding to ``str``.
+    :issue:`4157`
+-   Correctly handle raising deferred errors in CLI lazy loading.
+    :issue:`4096`
+-   The CLI loader handles ``**kwargs`` in a ``create_app`` function.
+    :issue:`4170`
+-   Fix the order of ``before_request`` and other callbacks that trigger
+    before the view returns. They are called from the app down to the
+    closest nested blueprint. :issue:`4229`
 
 
 Version 2.0.1
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 3a9177a4..a3c8b851 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -12,14 +12,16 @@ to address bugs and feature requests in Flask itself. Use one of the
 following resources for questions about using Flask or issues with your
 own code:
 
--   The ``#get-help`` channel on our Discord chat:
+-   The ``#questions`` channel on our Discord chat:
     https://discord.gg/pallets
 -   The mailing list flask@python.org for long term discussion or larger
     issues.
 -   Ask on `Stack Overflow`_. Search with Google first using:
     ``site:stackoverflow.com flask {search term, exception message, etc.}``
+-   Ask on our `GitHub Discussions`_.
 
 .. _Stack Overflow: https://stackoverflow.com/questions/tagged/flask?tab=Frequent
+.. _GitHub Discussions: https://github.com/pallets/flask/discussions
 
 
 Reporting issues
@@ -92,7 +94,7 @@ First time setup
 
     .. code-block:: text
 
-        git remote add fork https://github.com/{username}/flask
+        $ git remote add fork https://github.com/{username}/flask
 
 -   Create a virtualenv.
 
diff --git a/README.rst b/README.rst
index e389c6d6..b4f802f6 100644
--- a/README.rst
+++ b/README.rst
@@ -26,7 +26,7 @@ Install and update using `pip`_:
 
     $ pip install -U Flask
 
-.. _pip: https://pip.pypa.io/en/stable/quickstart/
+.. _pip: https://pip.pypa.io/en/stable/getting-started/
 
 
 A Simple Example
diff --git a/artwork/LICENSE.rst b/artwork/LICENSE.rst
index 605e41cb..99c58a21 100644
--- a/artwork/LICENSE.rst
+++ b/artwork/LICENSE.rst
@@ -10,7 +10,7 @@ following conditions are met:
 1.  Redistributions of source code must retain the above copyright
     notice and this list of conditions.
 
-3.  Neither the name of the copyright holder nor the names of its
+2.  Neither the name of the copyright holder nor the names of its
     contributors may be used to endorse or promote products derived from
     this software without specific prior written permission.
 
diff --git a/docs/api.rst b/docs/api.rst
index e6862878..5eb8b693 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -218,8 +218,6 @@ Useful Functions and Classes
 
 .. autofunction:: send_from_directory
 
-.. autofunction:: safe_join
-
 .. autofunction:: escape
 
 .. autoclass:: Markup
@@ -256,7 +254,7 @@ the filter to render data inside ``<script>`` tags.
 
 .. sourcecode:: html+jinja
 
-    <script type=text/javascript>
+    <script>
         const names = {{ names|tosjon }};
         renderChart(names, {{ axis_data|tojson }});
     </script>
diff --git a/docs/appcontext.rst b/docs/appcontext.rst
index 68176494..b214f254 100644
--- a/docs/appcontext.rst
+++ b/docs/appcontext.rst
@@ -8,7 +8,7 @@ a request, CLI command, or other activity. Rather than passing the
 application around to each function, the :data:`current_app` and
 :data:`g` proxies are accessed instead.
 
-This is similar to the :doc:`/reqcontext`, which keeps track of
+This is similar to :doc:`/reqcontext`, which keeps track of
 request-level data during a request. A corresponding application context
 is pushed when a request context is pushed.
 
diff --git a/docs/async-await.rst b/docs/async-await.rst
index 34751d47..4c70f961 100644
--- a/docs/async-await.rst
+++ b/docs/async-await.rst
@@ -17,12 +17,24 @@ defined with ``async def`` and use ``await``.
         data = await async_db_query(...)
         return jsonify(data)
 
+Pluggable class-based views also support handlers that are implemented as
+coroutines. This applies to the :meth:`~flask.views.View.dispatch_request`
+method in views that inherit from the :class:`flask.views.View` class, as
+well as all the HTTP method handlers in views that inherit from the
+:class:`flask.views.MethodView` class.
+
 .. admonition:: Using ``async`` on Windows on Python 3.8
 
     Python 3.8 has a bug related to asyncio on Windows. If you encounter
     something like ``ValueError: set_wakeup_fd only works in main thread``,
     please upgrade to Python 3.9.
 
+.. admonition:: Using ``async`` with greenlet
+
+    When using gevent or eventlet to serve an application or patch the
+    runtime, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is
+    required.
+
 
 Performance
 -----------
diff --git a/docs/cli.rst b/docs/cli.rst
index 6036cb2d..d32dd7be 100644
--- a/docs/cli.rst
+++ b/docs/cli.rst
@@ -103,6 +103,11 @@ replaces the :meth:`Flask.run` method in most cases. ::
     is provided for convenience, but is not designed to be particularly secure,
     stable, or efficient. See :doc:`/deploying/index` for how to run in production.
 
+If another program is already using port 5000, you'll see
+``OSError: [Errno 98]`` or ``OSError: [WinError 10013]`` when the
+server tries to start. See :ref:`address-already-in-use` for how to
+handle that.
+
 
 Open a Shell
 ------------
@@ -112,10 +117,9 @@ shell with the :func:`shell <cli.shell_command>` command. An application
 context will be active, and the app instance will be imported. ::
 
     $ flask shell
-    Python 3.6.2 (default, Jul 20 2017, 03:52:27)
-    [GCC 7.1.1 20170630] on linux
-    App: example
-    Instance: /home/user/Projects/hello/instance
+    Python 3.10.0 (default, Oct 27 2021, 06:59:51) [GCC 11.1.0] on linux
+    App: example [production]
+    Instance: /home/david/Projects/pallets/flask/instance
     >>>
 
 Use :meth:`~Flask.shell_context_processor` to add other automatic imports.
diff --git a/docs/config.rst b/docs/config.rst
index 768cf60d..ad737109 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -38,7 +38,7 @@ method::
 
     app.config.update(
         TESTING=True,
-        SECRET_KEY=b'_5#y2L"F4Q8z\n\xec]/'
+        SECRET_KEY='192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'
     )
 
 
@@ -180,8 +180,8 @@ The following configuration values are used internally by Flask:
     application. It should be a long random ``bytes`` or ``str``. For
     example, copy the output of this to your config::
 
-        $ python -c 'import os; print(os.urandom(16))'
-        b'_5#y2L"F4Q8z\n\xec]/'
+        $ python -c 'import secrets; print(secrets.token_hex())'
+        '192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'
 
     **Do not reveal the secret key when posting questions or committing code.**
 
@@ -468,7 +468,7 @@ sure to use uppercase letters for your config keys.
 Here is an example of a configuration file::
 
     # Example configuration
-    SECRET_KEY = b'_5#y2L"F4Q8z\n\xec]/'
+    SECRET_KEY = '192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'
 
 Make sure to load the configuration very early on, so that extensions have
 the ability to access the configuration when starting up.  There are other
diff --git a/docs/debugging.rst b/docs/debugging.rst
index a9f984b4..66118de2 100644
--- a/docs/debugging.rst
+++ b/docs/debugging.rst
@@ -69,7 +69,7 @@ enables the debugger and reloader.
 
 ``FLASK_ENV`` can only be set as an environment variable. When running
 from Python code, passing ``debug=True`` enables debug mode, which is
-mostly equivalent. Debug mode can be controled separately from
+mostly equivalent. Debug mode can be controlled separately from
 ``FLASK_ENV`` with the ``FLASK_DEBUG`` environment variable as well.
 
 .. code-block:: python
diff --git a/docs/deploying/asgi.rst b/docs/deploying/asgi.rst
index c7e04027..39cd76b7 100644
--- a/docs/deploying/asgi.rst
+++ b/docs/deploying/asgi.rst
@@ -5,7 +5,7 @@ ASGI
 
 If you'd like to use an ASGI server you will need to utilise WSGI to
 ASGI middleware. The asgiref
-[WsgiToAsgi](https://github.com/django/asgiref#wsgi-to-asgi-adapter)
+`WsgiToAsgi <https://github.com/django/asgiref#wsgi-to-asgi-adapter>`_
 adapter is recommended as it integrates with the event loop used for
 Flask's :ref:`async_await` support. You can use the adapter by
 wrapping the Flask app,
@@ -21,7 +21,7 @@ wrapping the Flask app,
 
     asgi_app = WsgiToAsgi(app)
 
-and then serving the ``asgi_app`` with the asgi server, e.g. using
+and then serving the ``asgi_app`` with the ASGI server, e.g. using
 `Hypercorn <https://gitlab.com/pgjones/hypercorn>`_,
 
 .. sourcecode:: text
diff --git a/docs/deploying/fastcgi.rst b/docs/deploying/fastcgi.rst
index ef2201c8..d3614d37 100644
--- a/docs/deploying/fastcgi.rst
+++ b/docs/deploying/fastcgi.rst
@@ -234,5 +234,5 @@ python path.  Common problems are:
 
 .. _nginx: https://nginx.org/
 .. _lighttpd: https://www.lighttpd.net/
-.. _cherokee: http://cherokee-project.com/
+.. _cherokee: https://cherokee-project.com/
 .. _flup: https://pypi.org/project/flup/
diff --git a/docs/deploying/uwsgi.rst b/docs/deploying/uwsgi.rst
index 22930d7b..b6958dc0 100644
--- a/docs/deploying/uwsgi.rst
+++ b/docs/deploying/uwsgi.rst
@@ -37,7 +37,7 @@ If your application is accessible at root level, you can use a
 single ``/`` instead of ``/yourapplication``. ``myapp`` refers to the name of
 the file of your flask application (without extension) or the module which
 provides ``app``. ``app`` is the callable inside of your application (usually
-the line reads ``app = Flask(__name__)``.
+the line reads ``app = Flask(__name__)``).
 
 If you want to deploy your flask application inside of a virtual environment,
 you need to also add ``--virtualenv /path/to/virtual/environment``. You might
@@ -67,5 +67,5 @@ to have it in the URL root its a bit simpler::
 
 .. _nginx: https://nginx.org/
 .. _lighttpd: https://www.lighttpd.net/
-.. _cherokee: http://cherokee-project.com/
+.. _cherokee: https://cherokee-project.com/
 .. _uwsgi: https://uwsgi-docs.readthedocs.io/en/latest/
diff --git a/docs/deploying/wsgi-standalone.rst b/docs/deploying/wsgi-standalone.rst
index 1339a625..823426ac 100644
--- a/docs/deploying/wsgi-standalone.rst
+++ b/docs/deploying/wsgi-standalone.rst
@@ -1,67 +1,171 @@
-Standalone WSGI Containers
-==========================
+Standalone WSGI Servers
+=======================
+
+Most WSGI servers also provide HTTP servers, so they can run a WSGI
+application and make it available externally.
+
+It may still be a good idea to run the server behind a dedicated HTTP
+server such as Apache or Nginx. See :ref:`deploying-proxy-setups` if you
+run into issues with that.
 
-There are popular servers written in Python that contain WSGI applications and
-serve HTTP.  These servers stand alone when they run; you can proxy to them
-from your web server.  Note the section on :ref:`deploying-proxy-setups` if you
-run into issues.
 
 Gunicorn
 --------
 
-`Gunicorn`_ 'Green Unicorn' is a WSGI HTTP Server for UNIX. It's a pre-fork
-worker model ported from Ruby's Unicorn project. It supports both `eventlet`_
-and `greenlet`_. Running a Flask application on this server is quite simple::
+`Gunicorn`_ is a WSGI and HTTP server for UNIX. To run a Flask
+application, tell Gunicorn how to import your Flask app object.
 
-    $ gunicorn myproject:app
+.. code-block:: text
 
-`Gunicorn`_ provides many command-line options -- see ``gunicorn -h``.
-For example, to run a Flask application with 4 worker processes (``-w
-4``) binding to localhost port 4000 (``-b 127.0.0.1:4000``)::
+    $ gunicorn -w 4 -b 0.0.0.0:5000 your_project:app
 
-    $ gunicorn -w 4 -b 127.0.0.1:4000 myproject:app
+The ``-w 4`` option uses 4 workers to handle 4 requests at once. The
+``-b 0.0.0.0:5000`` serves the application on all interfaces on port
+5000.
 
-The ``gunicorn`` command expects the names of your application module or
-package and the application instance within the module. If you use the
-application factory pattern, you can pass a call to that::
+Gunicorn provides many options for configuring the server, either
+through a configuration file or with command line options. Use
+``gunicorn --help`` or see the docs for more information.
+
+The command expects the name of your module or package to import and
+the application instance within the module. If you use the application
+factory pattern, you can pass a call to that.
+
+.. code-block:: text
+
+    $ gunicorn -w 4 -b 0.0.0.0:5000 "myproject:create_app()"
+
+
+Async with Gevent or Eventlet
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The default sync worker is appropriate for many use cases. If you need
+asynchronous support, Gunicorn provides workers using either `gevent`_
+or `eventlet`_. This is not the same as Python's ``async/await``, or the
+ASGI server spec.
+
+When using either gevent or eventlet, greenlet>=1.0 is required,
+otherwise context locals such as ``request`` will not work as expected.
+When using PyPy, PyPy>=7.3.7 is required.
+
+To use gevent:
+
+.. code-block:: text
+
+    $ gunicorn -k gevent -b 0.0.0.0:5000 your_project:app
+
+To use eventlet:
+
+.. code-block:: text
+
+    $ gunicorn -k eventlet -b 0.0.0.0:5000 your_project:app
 
-    $ gunicorn "myproject:create_app()"
 
 .. _Gunicorn: https://gunicorn.org/
+.. _gevent: http://www.gevent.org/
 .. _eventlet: https://eventlet.net/
+.. _greenlet: https://greenlet.readthedocs.io/en/latest/
 
 
 uWSGI
---------
+-----
 
-`uWSGI`_ is a fast application server written in C. It is very configurable
-which makes it more complicated to setup than gunicorn.
+`uWSGI`_ is a fast application server written in C. It is very
+configurable, which makes it more complicated to setup than Gunicorn.
+It also provides many other utilities for writing robust web
+applications. To run a Flask application, tell Gunicorn how to import
+your Flask app object.
 
-Running `uWSGI HTTP Router`_::
+.. code-block:: text
 
-    $ uwsgi --http 127.0.0.1:5000 --module myproject:app
+    $ uwsgi --master -p 4 --http 0.0.0.0:5000 -w your_project:app
 
-For a more optimized setup, see :doc:`configuring uWSGI and NGINX <uwsgi>`.
+The ``-p 4`` option uses 4 workers to handle 4 requests at once. The
+``--http 0.0.0.0:5000`` serves the application on all interfaces on port
+5000.
+
+uWSGI has optimized integration with Nginx and Apache instead of using
+a standard HTTP proxy. See :doc:`configuring uWSGI and Nginx <uwsgi>`.
+
+
+Async with Gevent
+~~~~~~~~~~~~~~~~~
+
+The default sync worker is appropriate for many use cases. If you need
+asynchronous support, uWSGI provides workers using `gevent`_. It also
+supports other async modes, see the docs for more information. This is
+not the same as Python's ``async/await``, or the ASGI server spec.
+
+When using gevent, greenlet>=1.0 is required, otherwise context locals
+such as ``request`` will not work as expected. When using PyPy,
+PyPy>=7.3.7 is required.
+
+.. code-block:: text
+
+    $ uwsgi --master --gevent 100 --http 0.0.0.0:5000 -w your_project:app
 
 .. _uWSGI: https://uwsgi-docs.readthedocs.io/en/latest/
-.. _uWSGI HTTP Router: https://uwsgi-docs.readthedocs.io/en/latest/HTTP.html#the-uwsgi-http-https-router
+
 
 Gevent
--------
+------
 
-`Gevent`_ is a coroutine-based Python networking library that uses
-`greenlet`_ to provide a high-level synchronous API on top of `libev`_
-event loop::
+Prefer using `Gunicorn`_ with Gevent workers rather than using Gevent
+directly. Gunicorn provides a much more configurable and
+production-tested server. See the section on Gunicorn above.
+
+`Gevent`_ allows writing asynchronous, coroutine-based code that looks
+like standard synchronous Python. It uses `greenlet`_ to enable task
+switching without writing ``async/await`` or using ``asyncio``.
+
+It provides a WSGI server that can handle many connections at once
+instead of one per worker process.
+
+`Eventlet`_, described below, is another library that does the same
+thing. Certain dependencies you have, or other consideration, may affect
+which of the two you choose to use
+
+To use gevent to serve your application, import its ``WSGIServer`` and
+use it to run your ``app``.
+
+.. code-block:: python
 
     from gevent.pywsgi import WSGIServer
-    from yourapplication import app
+    from your_project import app
 
-    http_server = WSGIServer(('', 5000), app)
+    http_server = WSGIServer(("", 5000), app)
     http_server.serve_forever()
 
-.. _Gevent: http://www.gevent.org/
-.. _greenlet: https://greenlet.readthedocs.io/en/latest/
-.. _libev: http://software.schmorp.de/pkg/libev.html
+
+Eventlet
+--------
+
+Prefer using `Gunicorn`_ with Eventlet workers rather than using
+Eventlet directly. Gunicorn provides a much more configurable and
+production-tested server. See the section on Gunicorn above.
+
+`Eventlet`_ allows writing asynchronous, coroutine-based code that looks
+like standard synchronous Python. It uses `greenlet`_ to enable task
+switching without writing ``async/await`` or using ``asyncio``.
+
+It provides a WSGI server that can handle many connections at once
+instead of one per worker process.
+
+`Gevent`_, described above, is another library that does the same
+thing. Certain dependencies you have, or other consideration, may affect
+which of the two you choose to use
+
+To use eventlet to serve your application, import its ``wsgi.server``
+and use it to run your ``app``.
+
+.. code-block:: python
+
+    import eventlet
+    from eventlet import wsgi
+    from your_project import app
+
+    wsgi.server(eventlet.listen(("", 5000), app)
+
 
 Twisted Web
 -----------
@@ -69,7 +173,9 @@ Twisted Web
 `Twisted Web`_ is the web server shipped with `Twisted`_, a mature,
 non-blocking event-driven networking library. Twisted Web comes with a
 standard WSGI container which can be controlled from the command line using
-the ``twistd`` utility::
+the ``twistd`` utility:
+
+.. code-block:: text
 
     $ twistd web --wsgi myproject.app
 
@@ -79,13 +185,16 @@ This example will run a Flask application called ``app`` from a module named
 Twisted Web supports many flags and options, and the ``twistd`` utility does
 as well; see ``twistd -h`` and ``twistd web -h`` for more information. For
 example, to run a Twisted Web server in the foreground, on port 8080, with an
-application from ``myproject``::
+application from ``myproject``:
+
+.. code-block:: text
 
     $ twistd -n web --port tcp:8080 --wsgi myproject.app
 
 .. _Twisted: https://twistedmatrix.com/trac/
 .. _Twisted Web: https://twistedmatrix.com/trac/wiki/TwistedWeb
 
+
 .. _deploying-proxy-setups:
 
 Proxy Setups
diff --git a/docs/extensiondev.rst b/docs/extensiondev.rst
index 18b4fa7d..dbaf62cb 100644
--- a/docs/extensiondev.rst
+++ b/docs/extensiondev.rst
@@ -322,9 +322,9 @@ ecosystem remain consistent and compatible.
     `Official Pallets Themes`_. A link to the documentation or project
     website must be in the PyPI metadata or the readme.
 7.  For maximum compatibility, the extension should support the same
-    versions of Python that Flask supports. 3.6+ is recommended as of
-    2020. Use ``python_requires=">= 3.6"`` in ``setup.py`` to indicate
-    supported versions.
+    versions of Python that Flask supports. 3.7+ is recommended as of
+    December 2021. Use ``python_requires=">= 3.7"`` in ``setup.py`` to
+    indicate supported versions.
 
 .. _PyPI: https://pypi.org/search/?c=Framework+%3A%3A+Flask
 .. _mailinglist: https://mail.python.org/mailman/listinfo/flask
diff --git a/docs/installation.rst b/docs/installation.rst
index aef7df0c..8a338e18 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -6,7 +6,7 @@ Python Version
 --------------
 
 We recommend using the latest version of Python. Flask supports Python
-3.6 and newer.
+3.7 and newer.
 
 
 Dependencies
@@ -49,6 +49,18 @@ use them if you install them.
 .. _watchdog: https://pythonhosted.org/watchdog/
 
 
+greenlet
+~~~~~~~~
+
+You may choose to use gevent or eventlet with your application. In this
+case, greenlet>=1.0 is required. When using PyPy, PyPy>=7.3.7 is
+required.
+
+These are not minimum supported versions, they only indicate the first
+versions that added necessary features. You should use the latest
+versions of each.
+
+
 Virtual environments
 --------------------
 
diff --git a/docs/patterns/celery.rst b/docs/patterns/celery.rst
index e1f6847e..38a9a025 100644
--- a/docs/patterns/celery.rst
+++ b/docs/patterns/celery.rst
@@ -64,7 +64,7 @@ An example task
 
 Let's write a task that adds two numbers together and returns the result. We
 configure Celery's broker and backend to use Redis, create a ``celery``
-application using the factor from above, and then use it to define the task. ::
+application using the factory from above, and then use it to define the task. ::
 
     from flask import Flask
 
diff --git a/docs/patterns/fileuploads.rst b/docs/patterns/fileuploads.rst
index f24a43ca..304f57dc 100644
--- a/docs/patterns/fileuploads.rst
+++ b/docs/patterns/fileuploads.rst
@@ -175,9 +175,8 @@ are JavaScript libraries like jQuery_ that have form plugins to ease the
 construction of progress bar.
 
 Because the common pattern for file uploads exists almost unchanged in all
-applications dealing with uploads, there is also a Flask extension called
-`Flask-Uploads`_ that implements a full fledged upload mechanism that
-allows controlling which file extensions are allowed to be uploaded.
+applications dealing with uploads, there are also some Flask extensions that
+implement a full fledged upload mechanism that allows controlling which
+file extensions are allowed to be uploaded.
 
 .. _jQuery: https://jquery.com/
-.. _Flask-Uploads: https://flask-uploads.readthedocs.io/en/latest/
diff --git a/docs/patterns/jquery.rst b/docs/patterns/jquery.rst
index fafbdf18..0a75bb71 100644
--- a/docs/patterns/jquery.rst
+++ b/docs/patterns/jquery.rst
@@ -23,8 +23,7 @@ to add a script statement to the bottom of your ``<body>`` to load jQuery:
 
 .. sourcecode:: html
 
-   <script type=text/javascript src="{{
-     url_for('static', filename='jquery.js') }}"></script>
+   <script src="{{ url_for('static', filename='jquery.js') }}"></script>
 
 Another method is using Google's `AJAX Libraries API
 <https://developers.google.com/speed/libraries/>`_ to load jQuery:
@@ -59,7 +58,7 @@ like this:
 
 .. sourcecode:: html+jinja
 
-   <script type=text/javascript>
+   <script>
      $SCRIPT_ROOT = {{ request.script_root|tojson }};
    </script>
 
@@ -109,7 +108,7 @@ usually a better idea to have that in a separate script file:
 
 .. sourcecode:: html
 
-    <script type=text/javascript>
+    <script>
       $(function() {
         $('a#calculate').bind('click', function() {
           $.getJSON($SCRIPT_ROOT + '/_add_numbers', {
diff --git a/docs/patterns/sqlite3.rst b/docs/patterns/sqlite3.rst
index 8cf596d3..12336fb1 100644
--- a/docs/patterns/sqlite3.rst
+++ b/docs/patterns/sqlite3.rst
@@ -113,16 +113,16 @@ raw cursor and connection objects.
 Here is how you can use it::
 
     for user in query_db('select * from users'):
-        print user['username'], 'has the id', user['user_id']
+        print(user['username'], 'has the id', user['user_id'])
 
 Or if you just want a single result::
 
     user = query_db('select * from users where username = ?',
                     [the_username], one=True)
     if user is None:
-        print 'No such user'
+        print('No such user')
     else:
-        print the_username, 'has the id', user['user_id']
+        print(the_username, 'has the id', user['user_id'])
 
 To pass variable parts to the SQL statement, use a question mark in the
 statement and pass in the arguments as a list.  Never directly add them to
diff --git a/docs/patterns/wtforms.rst b/docs/patterns/wtforms.rst
index e5fd500d..3d626f50 100644
--- a/docs/patterns/wtforms.rst
+++ b/docs/patterns/wtforms.rst
@@ -19,7 +19,7 @@ forms.
    fun.  You can get it from `PyPI
    <https://pypi.org/project/Flask-WTF/>`_.
 
-.. _Flask-WTF: https://flask-wtf.readthedocs.io/en/stable/
+.. _Flask-WTF: https://flask-wtf.readthedocs.io/
 
 The Forms
 ---------
diff --git a/docs/quickstart.rst b/docs/quickstart.rst
index 5cd59f41..283b8fc3 100644
--- a/docs/quickstart.rst
+++ b/docs/quickstart.rst
@@ -83,6 +83,11 @@ deployment options see :doc:`deploying/index`.
 Now head over to http://127.0.0.1:5000/, and you should see your hello
 world greeting.
 
+If another program is already using port 5000, you'll see
+``OSError: [Errno 98]`` or ``OSError: [WinError 10013]`` when the
+server tries to start. See :ref:`address-already-in-use` for how to
+handle that.
+
 .. _public-server:
 
 .. admonition:: Externally Visible Server
@@ -444,9 +449,9 @@ Here is an example template:
       <h1>Hello, World!</h1>
     {% endif %}
 
-Inside templates you also have access to the :class:`~flask.request`,
-:class:`~flask.session` and :class:`~flask.g` [#]_ objects
-as well as the :func:`~flask.get_flashed_messages` function.
+Inside templates you also have access to the :data:`~flask.Flask.config`,
+:class:`~flask.request`, :class:`~flask.session` and :class:`~flask.g` [#]_ objects
+as well as the :func:`~flask.url_for` and :func:`~flask.get_flashed_messages` functions.
 
 Templates are especially useful if inheritance is used.  If you want to
 know how that works, see :doc:`patterns/templateinheritance`. Basically
@@ -468,7 +473,7 @@ Here is a basic introduction to how the :class:`~markupsafe.Markup` class works:
     >>> Markup.escape('<blink>hacker</blink>')
     Markup('&lt;blink&gt;hacker&lt;/blink&gt;')
     >>> Markup('<em>Marked up</em> &raquo; HTML').striptags()
-    'Marked up \xbb HTML'
+    'Marked up » HTML'
 
 .. versionchanged:: 0.5
 
@@ -626,7 +631,7 @@ Werkzeug provides for you::
     def upload_file():
         if request.method == 'POST':
             file = request.files['the_file']
-            file.save(f"/var/www/uploads/{secure_filename(f.filename)}")
+            file.save(f"/var/www/uploads/{secure_filename(file.filename)}")
         ...
 
 For some better examples, see :doc:`patterns/fileuploads`.
@@ -847,8 +852,8 @@ sessions work::
     generator. Use the following command to quickly generate a value for
     :attr:`Flask.secret_key` (or :data:`SECRET_KEY`)::
 
-        $ python -c 'import os; print(os.urandom(16))'
-        b'_5#y2L"F4Q8z\n\xec]/'
+        $ python -c 'import secrets; print(secrets.token_hex())'
+        '192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'
 
 A note on cookie-based sessions: Flask will take the values you put into the
 session object and serialize them into a cookie.  If you are finding some
diff --git a/docs/reqcontext.rst b/docs/reqcontext.rst
index 31a83cff..b67745ed 100644
--- a/docs/reqcontext.rst
+++ b/docs/reqcontext.rst
@@ -8,7 +8,7 @@ request. Rather than passing the request object to each function that
 runs during a request, the :data:`request` and :data:`session` proxies
 are accessed instead.
 
-This is similar to the :doc:`/appcontext`, which keeps track of the
+This is similar to :doc:`/appcontext`, which keeps track of the
 application-level data independent of a request. A corresponding
 application context is pushed when a request context is pushed.
 
@@ -33,8 +33,8 @@ Lifetime of the Context
 -----------------------
 
 When a Flask application begins handling a request, it pushes a request
-context, which also pushes an :doc:`/appcontext`. When the request ends
-it pops the request context then the application context.
+context, which also pushes an :doc:`app context </appcontext>`. When the
+request ends it pops the request context then the application context.
 
 The context is unique to each thread (or other worker type).
 :data:`request` cannot be passed to another thread, the other thread
diff --git a/docs/server.rst b/docs/server.rst
index 71704e4a..77b25abb 100644
--- a/docs/server.rst
+++ b/docs/server.rst
@@ -64,6 +64,54 @@ and using the CLI.
     above.
 
 
+.. _address-already-in-use:
+
+Address already in use
+~~~~~~~~~~~~~~~~~~~~~~
+
+If another program is already using port 5000, you'll see an ``OSError``
+when the server tries to start. It may have one of the following
+messages:
+
+-   ``OSError: [Errno 98] Address already in use``
+-   ``OSError: [WinError 10013] An attempt was made to access a socket
+    in a way forbidden by its access permissions``
+
+Either identify and stop the other program, or use
+``flask run --port 5001`` to pick a different port.
+
+You can use ``netstat`` or ``lsof`` to identify what process id is using
+a port, then use other operating system tools stop that process. The
+following example shows that process id 6847 is using port 5000.
+
+.. tabs::
+
+    .. tab:: ``netstat`` (Linux)
+
+        .. code-block:: text
+
+            $ netstat -nlp | grep 5000
+            tcp 0 0 127.0.0.1:5000 0.0.0.0:* LISTEN 6847/python
+
+    .. tab:: ``lsof`` (macOS / Linux)
+
+        .. code-block:: text
+
+            $ lsof -P -i :5000
+            Python 6847 IPv4 TCP localhost:5000 (LISTEN)
+
+    .. tab:: ``netstat`` (Windows)
+
+        .. code-block:: text
+
+            > netstat -ano | findstr 5000
+            TCP 127.0.0.1:5000 0.0.0.0:0 LISTENING 6847
+
+macOS Monterey and later automatically starts a service that uses port
+5000. To disable the service, go to System Preferences, Sharing, and
+disable "AirPlay Receiver".
+
+
 Lazy or Eager Loading
 ~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/docs/shell.rst b/docs/shell.rst
index 47efba37..7e42e285 100644
--- a/docs/shell.rst
+++ b/docs/shell.rst
@@ -21,8 +21,7 @@ that these functions are not only there for interactive shell usage, but
 also for unit testing and other situations that require a faked request
 context.
 
-Generally it's recommended that you read the :doc:`reqcontext`
-chapter of the documentation first.
+Generally it's recommended that you read :doc:`reqcontext` first.
 
 Command Line Interface
 ----------------------
diff --git a/docs/signals.rst b/docs/signals.rst
index 1e5cdd65..27630de6 100644
--- a/docs/signals.rst
+++ b/docs/signals.rst
@@ -177,7 +177,7 @@ With Blinker 1.1 you can also easily subscribe to signals by using the new
 
     @template_rendered.connect_via(app)
     def when_template_rendered(sender, template, context, **extra):
-        print f'Template {template.name} is rendered with {context}'
+        print(f'Template {template.name} is rendered with {context}')
 
 Core Signals
 ------------
diff --git a/docs/templating.rst b/docs/templating.rst
index b0964df8..dcc757c3 100644
--- a/docs/templating.rst
+++ b/docs/templating.rst
@@ -37,7 +37,7 @@ by default:
 .. data:: config
    :noindex:
 
-   The current configuration object (:data:`flask.config`)
+   The current configuration object (:data:`flask.Flask.config`)
 
    .. versionadded:: 0.6
 
diff --git a/docs/testing.rst b/docs/testing.rst
index 2fedc600..061d46d2 100644
--- a/docs/testing.rst
+++ b/docs/testing.rst
@@ -48,20 +48,21 @@ the application for testing and initializes a new database::
     import pytest
 
     from flaskr import create_app
+    from flaskr.db import init_db
 
 
     @pytest.fixture
     def client():
-        db_fd, flaskr.app.config['DATABASE'] = tempfile.mkstemp()
-        flaskr.app.config['TESTING'] = True
+        db_fd, db_path = tempfile.mkstemp()
+        app = create_app({'TESTING': True, 'DATABASE': db_path})
 
-        with flaskr.app.test_client() as client:
-            with flaskr.app.app_context():
-                flaskr.init_db()
+        with app.test_client() as client:
+            with app.app_context():
+                init_db()
             yield client
 
         os.close(db_fd)
-        os.unlink(flaskr.app.config['DATABASE'])
+        os.unlink(db_path)
 
 This client fixture will be called by each individual test.  It gives us a
 simple interface to the application, where we can trigger test requests to the
@@ -224,13 +225,13 @@ temporarily.  With this you can access the :class:`~flask.request`,
 :class:`~flask.g` and :class:`~flask.session` objects like in view
 functions.  Here is a full example that demonstrates this approach::
 
-    import flask
+    from flask import Flask, request
 
-    app = flask.Flask(__name__)
+    app = Flask(__name__)
 
     with app.test_request_context('/?name=Peter'):
-        assert flask.request.path == '/'
-        assert flask.request.args['name'] == 'Peter'
+        assert request.path == '/'
+        assert request.args['name'] == 'Peter'
 
 All the other objects that are context bound can be used in the same
 way.
@@ -247,7 +248,7 @@ the test request context leaves the ``with`` block.  If you do want the
 :meth:`~flask.Flask.before_request` functions to be called as well, you
 need to call :meth:`~flask.Flask.preprocess_request` yourself::
 
-    app = flask.Flask(__name__)
+    app = Flask(__name__)
 
     with app.test_request_context('/?name=Peter'):
         app.preprocess_request()
@@ -260,7 +261,7 @@ If you want to call the :meth:`~flask.Flask.after_request` functions you
 need to call into :meth:`~flask.Flask.process_response` which however
 requires that you pass it a response object::
 
-    app = flask.Flask(__name__)
+    app = Flask(__name__)
 
     with app.test_request_context('/?name=Peter'):
         resp = Response('...')
@@ -329,7 +330,7 @@ context around for a little longer so that additional introspection can
 happen.  With Flask 0.4 this is possible by using the
 :meth:`~flask.Flask.test_client` with a ``with`` block::
 
-    app = flask.Flask(__name__)
+    app = Flask(__name__)
 
     with app.test_client() as c:
         rv = c.get('/?tequila=42')
@@ -353,7 +354,7 @@ keep the context around and access :data:`flask.session`::
 
     with app.test_client() as c:
         rv = c.get('/')
-        assert flask.session['foo'] == 42
+        assert session['foo'] == 42
 
 This however does not make it possible to also modify the session or to
 access the session before a request was fired.  Starting with Flask 0.8 we
diff --git a/docs/tutorial/deploy.rst b/docs/tutorial/deploy.rst
index d954b5e7..19aa87fc 100644
--- a/docs/tutorial/deploy.rst
+++ b/docs/tutorial/deploy.rst
@@ -88,9 +88,9 @@ You can use the following command to output a random secret key:
 
 .. code-block:: none
 
-    $ python -c 'import os; print(os.urandom(16))'
+    $ python -c 'import secrets; print(secrets.token_hex())'
 
-    b'_5#y2L"F4Q8z\n\xec]/'
+    '192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'
 
 Create the ``config.py`` file in the instance folder, which the factory
 will read from if it exists. Copy the generated value into it.
@@ -98,7 +98,7 @@ will read from if it exists. Copy the generated value into it.
 .. code-block:: python
     :caption: ``venv/var/flaskr-instance/config.py``
 
-    SECRET_KEY = b'_5#y2L"F4Q8z\n\xec]/'
+    SECRET_KEY = '192b9bdd22ab9ed4d12e236c78afcb9a393ec15f71bbf5dc987d54727823bcbf'
 
 You can also set any other necessary configuration here, although
 ``SECRET_KEY`` is the only one needed for Flaskr.
diff --git a/docs/tutorial/factory.rst b/docs/tutorial/factory.rst
index ade5d40b..c4a10a6d 100644
--- a/docs/tutorial/factory.rst
+++ b/docs/tutorial/factory.rst
@@ -177,4 +177,9 @@ Visit http://127.0.0.1:5000/hello in a browser and you should see the
 "Hello, World!" message. Congratulations, you're now running your Flask
 web application!
 
+If another program is already using port 5000, you'll see
+``OSError: [Errno 98]`` or ``OSError: [WinError 10013]`` when the
+server tries to start. See :ref:`address-already-in-use` for how to
+handle that.
+
 Continue to :doc:`database`.
diff --git a/docs/tutorial/layout.rst b/docs/tutorial/layout.rst
index cb4d74b0..b6a09f03 100644
--- a/docs/tutorial/layout.rst
+++ b/docs/tutorial/layout.rst
@@ -57,29 +57,29 @@ By the end, your project layout will look like this:
 
     /home/user/Projects/flask-tutorial
     ├── flaskr/
-    │   ├── __init__.py
-    │   ├── db.py
-    │   ├── schema.sql
-    │   ├── auth.py
-    │   ├── blog.py
-    │   ├── templates/
-    │   │   ├── base.html
-    │   │   ├── auth/
-    │   │   │   ├── login.html
-    │   │   │   └── register.html
-    │   │   └── blog/
-    │   │       ├── create.html
-    │   │       ├── index.html
-    │   │       └── update.html
-    │   └── static/
-    │       └── style.css
+    │   ├── __init__.py
+    │   ├── db.py
+    │   ├── schema.sql
+    │   ├── auth.py
+    │   ├── blog.py
+    │   ├── templates/
+    │   │   ├── base.html
+    │   │   ├── auth/
+    │   │   │   ├── login.html
+    │   │   │   └── register.html
+    │   │   └── blog/
+    │   │       ├── create.html
+    │   │       ├── index.html
+    │   │       └── update.html
+    │   └── static/
+    │       └── style.css
     ├── tests/
-    │   ├── conftest.py
-    │   ├── data.sql
-    │   ├── test_factory.py
-    │   ├── test_db.py
-    │   ├── test_auth.py
-    │   └── test_blog.py
+    │   ├── conftest.py
+    │   ├── data.sql
+    │   ├── test_factory.py
+    │   ├── test_db.py
+    │   ├── test_auth.py
+    │   └── test_blog.py
     ├── venv/
     ├── setup.py
     └── MANIFEST.in
diff --git a/docs/tutorial/tests.rst b/docs/tutorial/tests.rst
index d8f2a931..f97d19df 100644
--- a/docs/tutorial/tests.rst
+++ b/docs/tutorial/tests.rst
@@ -270,7 +270,7 @@ messages.
 
         with app.app_context():
             assert get_db().execute(
-                "select * from user where username = 'a'",
+                "SELECT * FROM user WHERE username = 'a'",
             ).fetchone() is not None
 
 
diff --git a/docs/tutorial/views.rst b/docs/tutorial/views.rst
index 2d5a01d3..7092dbc2 100644
--- a/docs/tutorial/views.rst
+++ b/docs/tutorial/views.rst
@@ -91,18 +91,18 @@ write templates to generate the HTML form.
                 error = 'Username is required.'
             elif not password:
                 error = 'Password is required.'
-            elif db.execute(
-                'SELECT id FROM user WHERE username = ?', (username,)
-            ).fetchone() is not None:
-                error = f"User {username} is already registered."
 
             if error is None:
-                db.execute(
-                    'INSERT INTO user (username, password) VALUES (?, ?)',
-                    (username, generate_password_hash(password))
-                )
-                db.commit()
-                return redirect(url_for('auth.login'))
+                try:
+                    db.execute(
+                        "INSERT INTO user (username, password) VALUES (?, ?)",
+                        (username, generate_password_hash(password)),
+                    )
+                    db.commit()
+                except db.IntegrityError:
+                    error = f"User {username} is already registered."
+                else:
+                    return redirect(url_for("auth.login"))
 
             flash(error)
 
@@ -125,26 +125,25 @@ Here's what the ``register`` view function is doing:
 
 #.  Validate that ``username`` and ``password`` are not empty.
 
-#.  Validate that ``username`` is not already registered by querying the
-    database and checking if a result is returned.
-    :meth:`db.execute <sqlite3.Connection.execute>` takes a SQL query
-    with ``?`` placeholders for any user input, and a tuple of values
-    to replace the placeholders with. The database library will take
-    care of escaping the values so you are not vulnerable to a
-    *SQL injection attack*.
-
-    :meth:`~sqlite3.Cursor.fetchone` returns one row from the query.
-    If the query returned no results, it returns ``None``. Later,
-    :meth:`~sqlite3.Cursor.fetchall` is used, which returns a list of
-    all results.
-
 #.  If validation succeeds, insert the new user data into the database.
-    For security, passwords should never be stored in the database
-    directly. Instead,
-    :func:`~werkzeug.security.generate_password_hash` is used to
-    securely hash the password, and that hash is stored. Since this
-    query modifies data, :meth:`db.commit() <sqlite3.Connection.commit>`
-    needs to be called afterwards to save the changes.
+
+    -   :meth:`db.execute <sqlite3.Connection.execute>` takes a SQL
+        query with ``?`` placeholders for any user input, and a tuple of
+        values to replace the placeholders with. The database library
+        will take care of escaping the values so you are not vulnerable
+        to a *SQL injection attack*.
+
+    -   For security, passwords should never be stored in the database
+        directly. Instead,
+        :func:`~werkzeug.security.generate_password_hash` is used to
+        securely hash the password, and that hash is stored. Since this
+        query modifies data,
+        :meth:`db.commit() <sqlite3.Connection.commit>` needs to be
+        called afterwards to save the changes.
+
+    -   An :exc:`sqlite3.IntegrityError` will occur if the username
+        already exists, which should be shown to the user as another
+        validation error.
 
 #.  After storing the user, they are redirected to the login page.
     :func:`url_for` generates the URL for the login view based on its
@@ -200,6 +199,11 @@ There are a few differences from the ``register`` view:
 
 #.  The user is queried first and stored in a variable for later use.
 
+    :meth:`~sqlite3.Cursor.fetchone` returns one row from the query.
+    If the query returned no results, it returns ``None``. Later,
+    :meth:`~sqlite3.Cursor.fetchall` will be used, which returns a list
+    of all results.
+
 #.  :func:`~werkzeug.security.check_password_hash` hashes the submitted
     password in the same way as the stored hash and securely compares
     them. If they match, the password is valid.
diff --git a/docs/views.rst b/docs/views.rst
index 1d2daec7..63d26c5c 100644
--- a/docs/views.rst
+++ b/docs/views.rst
@@ -113,8 +113,8 @@ Method Based Dispatching
 
 For RESTful APIs it's especially helpful to execute a different function
 for each HTTP method.  With the :class:`flask.views.MethodView` you can
-easily do that.  Each HTTP method maps to a function with the same name
-(just in lowercase)::
+easily do that.  Each HTTP method maps to a method of the class with the
+same name (just in lowercase)::
 
     from flask.views import MethodView
 
diff --git a/examples/tutorial/flaskr/auth.py b/examples/tutorial/flaskr/auth.py
index bcd3c672..b423e6ae 100644
--- a/examples/tutorial/flaskr/auth.py
+++ b/examples/tutorial/flaskr/auth.py
@@ -60,21 +60,21 @@ def register():
             error = "Username is required."
         elif not password:
             error = "Password is required."
-        elif (
-            db.execute("SELECT id FROM user WHERE username = ?", (username,)).fetchone()
-            is not None
-        ):
-            error = f"User {username} is already registered."
 
         if error is None:
-            # the name is available, store it in the database and go to
-            # the login page
-            db.execute(
-                "INSERT INTO user (username, password) VALUES (?, ?)",
-                (username, generate_password_hash(password)),
-            )
-            db.commit()
-            return redirect(url_for("auth.login"))
+            try:
+                db.execute(
+                    "INSERT INTO user (username, password) VALUES (?, ?)",
+                    (username, generate_password_hash(password)),
+                )
+                db.commit()
+            except db.IntegrityError:
+                # The username was already taken, which caused the
+                # commit to fail. Show a validation error.
+                error = f"User {username} is already registered."
+            else:
+                # Success, go to the login page.
+                return redirect(url_for("auth.login"))
 
         flash(error)
 
diff --git a/examples/tutorial/tests/test_auth.py b/examples/tutorial/tests/test_auth.py
index 3ac9a12c..0bc0a9db 100644
--- a/examples/tutorial/tests/test_auth.py
+++ b/examples/tutorial/tests/test_auth.py
@@ -16,7 +16,7 @@ def test_register(client, app):
     # test that the user was inserted into the database
     with app.app_context():
         assert (
-            get_db().execute("select * from user where username = 'a'").fetchone()
+            get_db().execute("SELECT * FROM user WHERE username = 'a'").fetchone()
             is not None
         )
 
diff --git a/requirements/dev.txt b/requirements/dev.txt
index 42133b83..456cb986 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -1,146 +1,163 @@
 #
-# This file is autogenerated by pip-compile
+# This file is autogenerated by pip-compile with python 3.10
 # To update, run:
 #
 #    pip-compile requirements/dev.in
 #
 alabaster==0.7.12
     # via sphinx
-appdirs==1.4.4
-    # via virtualenv
-asgiref==3.3.4
-    # via -r tests.in
+asgiref==3.4.1
+    # via -r requirements/tests.in
 attrs==21.2.0
     # via pytest
 babel==2.9.1
     # via sphinx
+backports.entry-points-selectable==1.1.1
+    # via virtualenv
 blinker==1.4
-    # via -r tests.in
-certifi==2020.12.5
+    # via -r requirements/tests.in
+certifi==2021.10.8
     # via requests
-cfgv==3.3.0
+cffi==1.15.0
+    # via cryptography
+cfgv==3.3.1
     # via pre-commit
-chardet==4.0.0
+charset-normalizer==2.0.9
     # via requests
-click==8.0.1
+click==8.0.3
     # via pip-tools
-distlib==0.3.1
+cryptography==36.0.1
+    # via -r requirements/typing.in
+distlib==0.3.4
     # via virtualenv
 docutils==0.16
     # via
     #   sphinx
     #   sphinx-tabs
-filelock==3.0.12
+filelock==3.4.0
     # via
     #   tox
     #   virtualenv
-greenlet==1.1.0
-    # via -r tests.in
-identify==2.2.4
+greenlet==1.1.2 ; python_version < "3.11"
+    # via -r requirements/tests.in
+identify==2.4.0
     # via pre-commit
-idna==2.10
+idna==3.3
     # via requests
-imagesize==1.2.0
+imagesize==1.3.0
     # via sphinx
 iniconfig==1.1.1
     # via pytest
-jinja2==3.0.1
+jinja2==3.0.3
     # via sphinx
 markupsafe==2.0.1
     # via jinja2
+mypy==0.930
+    # via -r requirements/typing.in
 mypy-extensions==0.4.3
     # via mypy
-mypy==0.812
-    # via -r typing.in
 nodeenv==1.6.0
     # via pre-commit
-packaging==20.9
+packaging==21.3
     # via
     #   pallets-sphinx-themes
     #   pytest
     #   sphinx
     #   tox
-pallets-sphinx-themes==2.0.1
-    # via -r docs.in
-pep517==0.10.0
+pallets-sphinx-themes==2.0.2
+    # via -r requirements/docs.in
+pep517==0.12.0
     # via pip-tools
-pip-tools==6.1.0
-    # via -r dev.in
-pluggy==0.13.1
+pip-tools==6.4.0
+    # via -r requirements/dev.in
+platformdirs==2.4.0
+    # via virtualenv
+pluggy==1.0.0
     # via
     #   pytest
     #   tox
-pre-commit==2.13.0
-    # via -r dev.in
-py==1.10.0
+pre-commit==2.16.0
+    # via -r requirements/dev.in
+py==1.11.0
     # via
     #   pytest
     #   tox
-pygments==2.9.0
+pycparser==2.21
+    # via cffi
+pygments==2.10.0
     # via
     #   sphinx
     #   sphinx-tabs
-pyparsing==2.4.7
+pyparsing==3.0.6
     # via packaging
-pytest==6.2.4
-    # via -r tests.in
-python-dotenv==0.17.1
-    # via -r tests.in
-pytz==2021.1
+pytest==6.2.5
+    # via -r requirements/tests.in
+python-dotenv==0.19.2
+    # via -r requirements/tests.in
+pytz==2021.3
     # via babel
-pyyaml==5.4.1
+pyyaml==6.0
     # via pre-commit
-requests==2.25.1
+requests==2.26.0
     # via sphinx
 six==1.16.0
     # via
     #   tox
     #   virtualenv
-snowballstemmer==2.1.0
+snowballstemmer==2.2.0
     # via sphinx
-sphinx-issues==1.2.0
-    # via -r docs.in
-sphinx-tabs==3.0.0
-    # via -r docs.in
-sphinx==4.0.2
+sphinx==4.3.2
     # via
-    #   -r docs.in
+    #   -r requirements/docs.in
     #   pallets-sphinx-themes
     #   sphinx-issues
     #   sphinx-tabs
     #   sphinxcontrib-log-cabinet
+sphinx-issues==1.2.0
+    # via -r requirements/docs.in
+sphinx-tabs==3.2.0
+    # via -r requirements/docs.in
 sphinxcontrib-applehelp==1.0.2
     # via sphinx
 sphinxcontrib-devhelp==1.0.2
     # via sphinx
-sphinxcontrib-htmlhelp==1.0.3
+sphinxcontrib-htmlhelp==2.0.0
     # via sphinx
 sphinxcontrib-jsmath==1.0.1
     # via sphinx
 sphinxcontrib-log-cabinet==1.0.1
-    # via -r docs.in
+    # via -r requirements/docs.in
 sphinxcontrib-qthelp==1.0.3
     # via sphinx
-sphinxcontrib-serializinghtml==1.1.4
+sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
 toml==0.10.2
     # via
-    #   pep517
     #   pre-commit
     #   pytest
     #   tox
-tox==3.23.1
-    # via -r dev.in
-typed-ast==1.4.3
+tomli==2.0.0
+    # via
+    #   mypy
+    #   pep517
+tox==3.24.4
+    # via -r requirements/dev.in
+types-contextvars==2.4.0
+    # via -r requirements/typing.in
+types-dataclasses==0.6.1
+    # via -r requirements/typing.in
+types-setuptools==57.4.4
+    # via -r requirements/typing.in
+typing-extensions==4.0.1
     # via mypy
-typing-extensions==3.10.0.0
-    # via mypy
-urllib3==1.26.5
+urllib3==1.26.7
     # via requests
-virtualenv==20.4.6
+virtualenv==20.10.0
     # via
     #   pre-commit
     #   tox
+wheel==0.37.1
+    # via pip-tools
 
 # The following packages are considered to be unsafe in a requirements file:
 # pip
diff --git a/requirements/docs.txt b/requirements/docs.txt
index f1ee1f27..1b51a429 100644
--- a/requirements/docs.txt
+++ b/requirements/docs.txt
@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile
+# This file is autogenerated by pip-compile with python 3.10
 # To update, run:
 #
 #    pip-compile requirements/docs.in
@@ -8,66 +8,66 @@ alabaster==0.7.12
     # via sphinx
 babel==2.9.1
     # via sphinx
-certifi==2020.12.5
+certifi==2021.10.8
     # via requests
-chardet==4.0.0
+charset-normalizer==2.0.9
     # via requests
 docutils==0.16
     # via
     #   sphinx
     #   sphinx-tabs
-idna==2.10
+idna==3.3
     # via requests
-imagesize==1.2.0
+imagesize==1.3.0
     # via sphinx
-jinja2==3.0.1
+jinja2==3.0.3
     # via sphinx
 markupsafe==2.0.1
     # via jinja2
-packaging==20.9
+packaging==21.3
     # via
     #   pallets-sphinx-themes
     #   sphinx
-pallets-sphinx-themes==2.0.1
-    # via -r docs.in
-pygments==2.9.0
+pallets-sphinx-themes==2.0.2
+    # via -r requirements/docs.in
+pygments==2.10.0
     # via
     #   sphinx
     #   sphinx-tabs
-pyparsing==2.4.7
+pyparsing==3.0.6
     # via packaging
-pytz==2021.1
+pytz==2021.3
     # via babel
-requests==2.25.1
+requests==2.26.0
     # via sphinx
-snowballstemmer==2.1.0
+snowballstemmer==2.2.0
     # via sphinx
-sphinx-issues==1.2.0
-    # via -r docs.in
-sphinx-tabs==3.0.0
-    # via -r docs.in
-sphinx==4.0.2
+sphinx==4.3.2
     # via
-    #   -r docs.in
+    #   -r requirements/docs.in
     #   pallets-sphinx-themes
     #   sphinx-issues
     #   sphinx-tabs
     #   sphinxcontrib-log-cabinet
+sphinx-issues==1.2.0
+    # via -r requirements/docs.in
+sphinx-tabs==3.2.0
+    # via -r requirements/docs.in
 sphinxcontrib-applehelp==1.0.2
     # via sphinx
 sphinxcontrib-devhelp==1.0.2
     # via sphinx
-sphinxcontrib-htmlhelp==1.0.3
+sphinxcontrib-htmlhelp==2.0.0
     # via sphinx
 sphinxcontrib-jsmath==1.0.1
     # via sphinx
 sphinxcontrib-log-cabinet==1.0.1
-    # via -r docs.in
+    # via -r requirements/docs.in
 sphinxcontrib-qthelp==1.0.3
     # via sphinx
-sphinxcontrib-serializinghtml==1.1.4
+sphinxcontrib-serializinghtml==1.1.5
     # via sphinx
-urllib3==1.26.5
+urllib3==1.26.7
     # via requests
 
 # The following packages are considered to be unsafe in a requirements file:
diff --git a/requirements/tests-pallets-dev.in b/requirements/tests-pallets-dev.in
new file mode 100644
index 00000000..dddbe48a
--- /dev/null
+++ b/requirements/tests-pallets-dev.in
@@ -0,0 +1,5 @@
+https://github.com/pallets/werkzeug/archive/refs/heads/main.tar.gz
+https://github.com/pallets/jinja/archive/refs/heads/main.tar.gz
+https://github.com/pallets/markupsafe/archive/refs/heads/main.tar.gz
+https://github.com/pallets/itsdangerous/archive/refs/heads/main.tar.gz
+https://github.com/pallets/click/archive/refs/heads/main.tar.gz
diff --git a/requirements/tests-pallets-dev.txt b/requirements/tests-pallets-dev.txt
new file mode 100644
index 00000000..19894ed6
--- /dev/null
+++ b/requirements/tests-pallets-dev.txt
@@ -0,0 +1,18 @@
+#
+# This file is autogenerated by pip-compile with python 3.10
+# To update, run:
+#
+#    pip-compile requirements/tests-pallets-dev.in
+#
+click @ https://github.com/pallets/click/archive/refs/heads/main.tar.gz
+    # via -r requirements/tests-pallets-dev.in
+itsdangerous @ https://github.com/pallets/itsdangerous/archive/refs/heads/main.tar.gz
+    # via -r requirements/tests-pallets-dev.in
+jinja2 @ https://github.com/pallets/jinja/archive/refs/heads/main.tar.gz
+    # via -r requirements/tests-pallets-dev.in
+markupsafe @ https://github.com/pallets/markupsafe/archive/refs/heads/main.tar.gz
+    # via
+    #   -r requirements/tests-pallets-dev.in
+    #   jinja2
+werkzeug @ https://github.com/pallets/werkzeug/archive/refs/heads/main.tar.gz
+    # via -r requirements/tests-pallets-dev.in
diff --git a/requirements/tests-pallets-min.in b/requirements/tests-pallets-min.in
new file mode 100644
index 00000000..6c8a55d9
--- /dev/null
+++ b/requirements/tests-pallets-min.in
@@ -0,0 +1,5 @@
+Werkzeug==2.0.0
+Jinja2==3.0.0
+MarkupSafe==2.0.0
+itsdangerous==2.0.0
+click==8.0.0
diff --git a/requirements/tests-pallets-min.txt b/requirements/tests-pallets-min.txt
new file mode 100644
index 00000000..75b3524c
--- /dev/null
+++ b/requirements/tests-pallets-min.txt
@@ -0,0 +1,18 @@
+#
+# This file is autogenerated by pip-compile with python 3.10
+# To update, run:
+#
+#    pip-compile requirements/tests-pallets-min.in
+#
+click==8.0.0
+    # via -r requirements/tests-pallets-min.in
+itsdangerous==2.0.0
+    # via -r requirements/tests-pallets-min.in
+jinja2==3.0.0
+    # via -r requirements/tests-pallets-min.in
+markupsafe==2.0.0
+    # via
+    #   -r requirements/tests-pallets-min.in
+    #   jinja2
+werkzeug==2.0.0
+    # via -r requirements/tests-pallets-min.in
diff --git a/requirements/tests.in b/requirements/tests.in
index 88fe5481..41936997 100644
--- a/requirements/tests.in
+++ b/requirements/tests.in
@@ -1,5 +1,5 @@
 pytest
 asgiref
 blinker
-greenlet
+greenlet ; python_version < "3.11"
 python-dotenv
diff --git a/requirements/tests.txt b/requirements/tests.txt
index deb93d62..f764cb7a 100644
--- a/requirements/tests.txt
+++ b/requirements/tests.txt
@@ -1,30 +1,30 @@
 #
-# This file is autogenerated by pip-compile
+# This file is autogenerated by pip-compile with python 3.10
 # To update, run:
 #
 #    pip-compile requirements/tests.in
 #
-asgiref==3.3.4
+asgiref==3.4.1
     # via -r requirements/tests.in
 attrs==21.2.0
     # via pytest
 blinker==1.4
     # via -r requirements/tests.in
-greenlet==1.1.0
+greenlet==1.1.2 ; python_version < "3.11"
     # via -r requirements/tests.in
 iniconfig==1.1.1
     # via pytest
-packaging==20.9
+packaging==21.3
     # via pytest
-pluggy==0.13.1
+pluggy==1.0.0
     # via pytest
-py==1.10.0
+py==1.11.0
     # via pytest
-pyparsing==2.4.7
+pyparsing==3.0.6
     # via packaging
-pytest==6.2.4
+pytest==6.2.5
     # via -r requirements/tests.in
-python-dotenv==0.17.1
+python-dotenv==0.19.2
     # via -r requirements/tests.in
 toml==0.10.2
     # via pytest
diff --git a/requirements/typing.in b/requirements/typing.in
index f0aa93ac..2c589ea0 100644
--- a/requirements/typing.in
+++ b/requirements/typing.in
@@ -1 +1,5 @@
 mypy
+types-contextvars
+types-dataclasses
+types-setuptools
+cryptography
diff --git a/requirements/typing.txt b/requirements/typing.txt
index 0e342aaa..5e1982a6 100644
--- a/requirements/typing.txt
+++ b/requirements/typing.txt
@@ -1,14 +1,26 @@
 #
-# This file is autogenerated by pip-compile
+# This file is autogenerated by pip-compile with python 3.10
 # To update, run:
 #
 #    pip-compile requirements/typing.in
 #
+cffi==1.15.0
+    # via cryptography
+cryptography==36.0.1
+    # via -r requirements/typing.in
+mypy==0.930
+    # via -r requirements/typing.in
 mypy-extensions==0.4.3
     # via mypy
-mypy==0.812
+pycparser==2.21
+    # via cffi
+tomli==2.0.0
+    # via mypy
+types-contextvars==2.4.0
     # via -r requirements/typing.in
-typed-ast==1.4.3
-    # via mypy
-typing-extensions==3.10.0.0
+types-dataclasses==0.6.1
+    # via -r requirements/typing.in
+types-setuptools==57.4.4
+    # via -r requirements/typing.in
+typing-extensions==4.0.1
     # via mypy
diff --git a/setup.cfg b/setup.cfg
index 77616866..131b3ad3 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -35,7 +35,7 @@ classifiers =
 packages = find:
 package_dir = = src
 include_package_data = true
-python_requires = >= 3.6
+python_requires = >= 3.7
 # Dependencies are in setup.py for GitHub's dependency graph.
 
 [options.packages.find]
@@ -88,7 +88,7 @@ per-file-ignores =
 
 [mypy]
 files = src/flask
-python_version = 3.6
+python_version = 3.7
 allow_redefinition = True
 disallow_subclassing_any = True
 # disallow_untyped_calls = True
@@ -112,3 +112,6 @@ ignore_missing_imports = True
 
 [mypy-dotenv.*]
 ignore_missing_imports = True
+
+[mypy-cryptography.*]
+ignore_missing_imports = True
diff --git a/src/flask/__init__.py b/src/flask/__init__.py
index 3e7198a6..e6987709 100644
--- a/src/flask/__init__.py
+++ b/src/flask/__init__.py
@@ -23,7 +23,6 @@ from .helpers import flash as flash
 from .helpers import get_flashed_messages as get_flashed_messages
 from .helpers import get_template_attribute as get_template_attribute
 from .helpers import make_response as make_response
-from .helpers import safe_join as safe_join
 from .helpers import send_file as send_file
 from .helpers import send_from_directory as send_from_directory
 from .helpers import stream_with_context as stream_with_context
diff --git a/src/flask/app.py b/src/flask/app.py
index cacb40a5..7c4076c5 100644
--- a/src/flask/app.py
+++ b/src/flask/app.py
@@ -16,7 +16,6 @@ from werkzeug.exceptions import BadRequest
 from werkzeug.exceptions import BadRequestKeyError
 from werkzeug.exceptions import HTTPException
 from werkzeug.exceptions import InternalServerError
-from werkzeug.local import ContextVar
 from werkzeug.routing import BuildError
 from werkzeug.routing import Map
 from werkzeug.routing import MapAdapter
@@ -58,18 +57,12 @@ from .signals import request_started
 from .signals import request_tearing_down
 from .templating import DispatchingJinjaLoader
 from .templating import Environment
-from .typing import AfterRequestCallable
 from .typing import BeforeFirstRequestCallable
-from .typing import BeforeRequestCallable
-from .typing import ErrorHandlerCallable
 from .typing import ResponseReturnValue
 from .typing import TeardownCallable
-from .typing import TemplateContextProcessorCallable
 from .typing import TemplateFilterCallable
 from .typing import TemplateGlobalCallable
 from .typing import TemplateTestCallable
-from .typing import URLDefaultCallable
-from .typing import URLValuePreprocessorCallable
 from .wrappers import Request
 from .wrappers import Response
 
@@ -78,6 +71,7 @@ if t.TYPE_CHECKING:
     from .blueprints import Blueprint
     from .testing import FlaskClient
     from .testing import FlaskCliRunner
+    from .typing import ErrorHandlerCallable
 
 if sys.version_info >= (3, 8):
     iscoroutinefunction = inspect.iscoroutinefunction
@@ -366,7 +360,8 @@ class Flask(Scaffold):
     #: .. versionadded:: 1.1.0
     url_map_class = Map
 
-    #: the test client that is used with when `test_client` is used.
+    #: The :meth:`test_client` method creates an instance of this test
+    #: client class. Defaults to :class:`~flask.testing.FlaskClient`.
     #:
     #: .. versionadded:: 0.7
     test_client_class: t.Optional[t.Type["FlaskClient"]] = None
@@ -389,7 +384,7 @@ class Flask(Scaffold):
         self,
         import_name: str,
         static_url_path: t.Optional[str] = None,
-        static_folder: t.Optional[str] = "static",
+        static_folder: t.Optional[t.Union[str, os.PathLike]] = "static",
         static_host: t.Optional[str] = None,
         host_matching: bool = False,
         subdomain_matching: bool = False,
@@ -744,20 +739,21 @@ class Flask(Scaffold):
         :param context: the context as a dictionary that is updated in place
                         to add extra variables.
         """
-        funcs: t.Iterable[
-            TemplateContextProcessorCallable
-        ] = self.template_context_processors[None]
-        reqctx = _request_ctx_stack.top
-        if reqctx is not None:
-            for bp in request.blueprints:
-                if bp in self.template_context_processors:
-                    funcs = chain(funcs, self.template_context_processors[bp])
+        names: t.Iterable[t.Optional[str]] = (None,)
+
+        # A template may be rendered outside a request context.
+        if request:
+            names = chain(names, reversed(request.blueprints))
+
+        # The values passed to render_template take precedence. Keep a
+        # copy to re-apply after all context functions.
         orig_ctx = context.copy()
-        for func in funcs:
-            context.update(func())
-        # make sure the original values win.  This makes it possible to
-        # easier add new variables in context processors without breaking
-        # existing views.
+
+        for name in names:
+            if name in self.template_context_processors:
+                for func in self.template_context_processors[name]:
+                    context.update(func())
+
         context.update(orig_ctx)
 
     def make_shell_context(self) -> dict:
@@ -1268,16 +1264,19 @@ class Flask(Scaffold):
         self.shell_context_processors.append(f)
         return f
 
-    def _find_error_handler(self, e: Exception) -> t.Optional[ErrorHandlerCallable]:
+    def _find_error_handler(
+        self, e: Exception
+    ) -> t.Optional["ErrorHandlerCallable[Exception]"]:
         """Return a registered error handler for an exception in this order:
         blueprint handler for a specific code, app handler for a specific code,
         blueprint handler for an exception class, app handler for an exception
         class, or ``None`` if a suitable handler is not found.
         """
         exc_class, code = self._get_exc_class_and_code(type(e))
+        names = (*request.blueprints, None)
 
-        for c in [code, None]:
-            for name in chain(request.blueprints, [None]):
+        for c in (code, None) if code is not None else (None,):
+            for name in names:
                 handler_map = self.error_handler_spec[name][c]
 
                 if not handler_map:
@@ -1304,7 +1303,7 @@ class Flask(Scaffold):
 
         .. versionchanged:: 1.0
             Exceptions are looked up by code *and* by MRO, so
-            ``HTTPExcpetion`` subclasses can be handled with a catch-all
+            ``HTTPException`` subclasses can be handled with a catch-all
             handler for the base ``HTTPException``.
 
         .. versionadded:: 0.3
@@ -1619,14 +1618,7 @@ class Flask(Scaffold):
         except ImportError:
             raise RuntimeError(
                 "Install Flask with the 'async' extra in order to use async views."
-            )
-
-        # Check that Werkzeug isn't using its fallback ContextVar class.
-        if ContextVar.__module__ == "werkzeug.local":
-            raise RuntimeError(
-                "Async cannot be used with this combination of Python "
-                "and Greenlet versions."
-            )
+            ) from None
 
         return asgiref_async_to_sync(func)
 
@@ -1725,7 +1717,7 @@ class Flask(Scaffold):
                         " response. The return type must be a string,"
                         " dict, tuple, Response instance, or WSGI"
                         f" callable, but it was a {type(rv).__name__}."
-                    ).with_traceback(sys.exc_info()[2])
+                    ).with_traceback(sys.exc_info()[2]) from None
             else:
                 raise TypeError(
                     "The view function did not return a valid"
@@ -1797,17 +1789,19 @@ class Flask(Scaffold):
 
         .. versionadded:: 0.7
         """
-        funcs: t.Iterable[URLDefaultCallable] = self.url_default_functions[None]
+        names: t.Iterable[t.Optional[str]] = (None,)
 
+        # url_for may be called outside a request context, parse the
+        # passed endpoint instead of using request.blueprints.
         if "." in endpoint:
-            # This is called by url_for, which can be called outside a
-            # request, can't use request.blueprints.
-            bps = _split_blueprint_path(endpoint.rpartition(".")[0])
-            bp_funcs = chain.from_iterable(self.url_default_functions[bp] for bp in bps)
-            funcs = chain(funcs, bp_funcs)
+            names = chain(
+                names, reversed(_split_blueprint_path(endpoint.rpartition(".")[0]))
+            )
 
-        for func in funcs:
-            func(endpoint, values)
+        for name in names:
+            if name in self.url_default_functions:
+                for func in self.url_default_functions[name]:
+                    func(endpoint, values)
 
     def handle_url_build_error(
         self, error: Exception, endpoint: str, values: dict
@@ -1842,24 +1836,20 @@ class Flask(Scaffold):
         value is handled as if it was the return value from the view, and
         further request handling is stopped.
         """
+        names = (None, *reversed(request.blueprints))
 
-        funcs: t.Iterable[URLValuePreprocessorCallable] = self.url_value_preprocessors[
-            None
-        ]
-        for bp in request.blueprints:
-            if bp in self.url_value_preprocessors:
-                funcs = chain(funcs, self.url_value_preprocessors[bp])
-        for func in funcs:
-            func(request.endpoint, request.view_args)
+        for name in names:
+            if name in self.url_value_preprocessors:
+                for url_func in self.url_value_preprocessors[name]:
+                    url_func(request.endpoint, request.view_args)
 
-        funcs: t.Iterable[BeforeRequestCallable] = self.before_request_funcs[None]
-        for bp in request.blueprints:
-            if bp in self.before_request_funcs:
-                funcs = chain(funcs, self.before_request_funcs[bp])
-        for func in funcs:
-            rv = self.ensure_sync(func)()
-            if rv is not None:
-                return rv
+        for name in names:
+            if name in self.before_request_funcs:
+                for before_func in self.before_request_funcs[name]:
+                    rv = self.ensure_sync(before_func)()
+
+                    if rv is not None:
+                        return rv
 
         return None
 
@@ -1877,16 +1867,18 @@ class Flask(Scaffold):
                  instance of :attr:`response_class`.
         """
         ctx = _request_ctx_stack.top
-        funcs: t.Iterable[AfterRequestCallable] = ctx._after_request_functions
-        for bp in request.blueprints:
-            if bp in self.after_request_funcs:
-                funcs = chain(funcs, reversed(self.after_request_funcs[bp]))
-        if None in self.after_request_funcs:
-            funcs = chain(funcs, reversed(self.after_request_funcs[None]))
-        for handler in funcs:
-            response = self.ensure_sync(handler)(response)
+
+        for func in ctx._after_request_functions:
+            response = self.ensure_sync(func)(response)
+
+        for name in chain(request.blueprints, (None,)):
+            if name in self.after_request_funcs:
+                for func in reversed(self.after_request_funcs[name]):
+                    response = self.ensure_sync(func)(response)
+
         if not self.session_interface.is_null_session(ctx.session):
             self.session_interface.save_session(self, ctx.session, response)
+
         return response
 
     def do_teardown_request(
@@ -1914,14 +1906,12 @@ class Flask(Scaffold):
         """
         if exc is _sentinel:
             exc = sys.exc_info()[1]
-        funcs: t.Iterable[TeardownCallable] = reversed(
-            self.teardown_request_funcs[None]
-        )
-        for bp in request.blueprints:
-            if bp in self.teardown_request_funcs:
-                funcs = chain(funcs, reversed(self.teardown_request_funcs[bp]))
-        for func in funcs:
-            self.ensure_sync(func)(exc)
+
+        for name in chain(request.blueprints, (None,)):
+            if name in self.teardown_request_funcs:
+                for func in reversed(self.teardown_request_funcs[name]):
+                    self.ensure_sync(func)(exc)
+
         request_tearing_down.send(self, exc=exc)
 
     def do_teardown_appcontext(
@@ -1943,8 +1933,10 @@ class Flask(Scaffold):
         """
         if exc is _sentinel:
             exc = sys.exc_info()[1]
+
         for func in reversed(self.teardown_appcontext_funcs):
             self.ensure_sync(func)(exc)
+
         appcontext_tearing_down.send(self, exc=exc)
 
     def app_context(self) -> AppContext:
diff --git a/src/flask/blueprints.py b/src/flask/blueprints.py
index 883fc2ff..47465ad7 100644
--- a/src/flask/blueprints.py
+++ b/src/flask/blueprints.py
@@ -1,3 +1,4 @@
+import os
 import typing as t
 from collections import defaultdict
 from functools import update_wrapper
@@ -8,7 +9,6 @@ from .scaffold import Scaffold
 from .typing import AfterRequestCallable
 from .typing import BeforeFirstRequestCallable
 from .typing import BeforeRequestCallable
-from .typing import ErrorHandlerCallable
 from .typing import TeardownCallable
 from .typing import TemplateContextProcessorCallable
 from .typing import TemplateFilterCallable
@@ -19,6 +19,7 @@ from .typing import URLValuePreprocessorCallable
 
 if t.TYPE_CHECKING:
     from .app import Flask
+    from .typing import ErrorHandlerCallable
 
 DeferredSetupFunction = t.Callable[["BlueprintSetupState"], t.Callable]
 
@@ -175,7 +176,7 @@ class Blueprint(Scaffold):
         self,
         name: str,
         import_name: str,
-        static_folder: t.Optional[str] = None,
+        static_folder: t.Optional[t.Union[str, os.PathLike]] = None,
         static_url_path: t.Optional[str] = None,
         template_folder: t.Optional[str] = None,
         url_prefix: t.Optional[str] = None,
@@ -293,34 +294,26 @@ class Blueprint(Scaffold):
             Registering the same blueprint with the same name multiple
             times is deprecated and will become an error in Flask 2.1.
         """
-        first_registration = not any(bp is self for bp in app.blueprints.values())
         name_prefix = options.get("name_prefix", "")
         self_name = options.get("name", self.name)
         name = f"{name_prefix}.{self_name}".lstrip(".")
 
         if name in app.blueprints:
+            bp_desc = "this" if app.blueprints[name] is self else "a different"
             existing_at = f" '{name}'" if self_name != name else ""
 
-            if app.blueprints[name] is not self:
-                raise ValueError(
-                    f"The name '{self_name}' is already registered for"
-                    f" a different blueprint{existing_at}. Use 'name='"
-                    " to provide a unique name."
-                )
-            else:
-                import warnings
+            raise ValueError(
+                f"The name '{self_name}' is already registered for"
+                f" {bp_desc} blueprint{existing_at}. Use 'name=' to"
+                f" provide a unique name."
+            )
 
-                warnings.warn(
-                    f"The name '{self_name}' is already registered for"
-                    f" this blueprint{existing_at}. Use 'name=' to"
-                    " provide a unique name. This will become an error"
-                    " in Flask 2.1.",
-                    stacklevel=4,
-                )
+        first_bp_registration = not any(bp is self for bp in app.blueprints.values())
+        first_name_registration = name not in app.blueprints
 
         app.blueprints[name] = self
         self._got_registered_once = True
-        state = self.make_setup_state(app, options, first_registration)
+        state = self.make_setup_state(app, options, first_bp_registration)
 
         if self.has_static_folder:
             state.add_url_rule(
@@ -330,7 +323,7 @@ class Blueprint(Scaffold):
             )
 
         # Merge blueprint data into parent.
-        if first_registration:
+        if first_bp_registration or first_name_registration:
 
             def extend(bp_dict, parent_dict):
                 for key, values in bp_dict.items():
@@ -581,7 +574,9 @@ class Blueprint(Scaffold):
         handler is used for all requests, even if outside of the blueprint.
         """
 
-        def decorator(f: ErrorHandlerCallable) -> ErrorHandlerCallable:
+        def decorator(
+            f: "ErrorHandlerCallable[Exception]",
+        ) -> "ErrorHandlerCallable[Exception]":
             self.record_once(lambda s: s.app.errorhandler(code)(f))
             return f
 
diff --git a/src/flask/cli.py b/src/flask/cli.py
index d9e810da..92bb60d6 100644
--- a/src/flask/cli.py
+++ b/src/flask/cli.py
@@ -5,7 +5,6 @@ import platform
 import re
 import sys
 import traceback
-import warnings
 from functools import update_wrapper
 from operator import attrgetter
 from threading import Lock
@@ -34,7 +33,7 @@ class NoAppException(click.UsageError):
     """Raised if an application cannot be found or loaded."""
 
 
-def find_best_app(script_info, module):
+def find_best_app(module):
     """Given a module instance this tries to find the best possible
     application in the module or raises an exception.
     """
@@ -65,19 +64,20 @@ def find_best_app(script_info, module):
 
         if inspect.isfunction(app_factory):
             try:
-                app = call_factory(script_info, app_factory)
+                app = app_factory()
 
                 if isinstance(app, Flask):
                     return app
-            except TypeError:
+            except TypeError as e:
                 if not _called_with_wrong_args(app_factory):
                     raise
+
                 raise NoAppException(
                     f"Detected factory {attr_name!r} in module {module.__name__!r},"
                     " but could not call it without arguments. Use"
                     f" \"FLASK_APP='{module.__name__}:{attr_name}(args)'\""
                     " to specify arguments."
-                )
+                ) from e
 
     raise NoAppException(
         "Failed to find Flask application or factory in module"
@@ -86,39 +86,6 @@ def find_best_app(script_info, module):
     )
 
 
-def call_factory(script_info, app_factory, args=None, kwargs=None):
-    """Takes an app factory, a ``script_info` object and  optionally a tuple
-    of arguments. Checks for the existence of a script_info argument and calls
-    the app_factory depending on that and the arguments provided.
-    """
-    sig = inspect.signature(app_factory)
-    args = [] if args is None else args
-    kwargs = {} if kwargs is None else kwargs
-
-    if "script_info" in sig.parameters:
-        warnings.warn(
-            "The 'script_info' argument is deprecated and will not be"
-            " passed to the app factory function in Flask 2.1.",
-            DeprecationWarning,
-        )
-        kwargs["script_info"] = script_info
-
-    if (
-        not args
-        and len(sig.parameters) == 1
-        and next(iter(sig.parameters.values())).default is inspect.Parameter.empty
-    ):
-        warnings.warn(
-            "Script info is deprecated and will not be passed as the"
-            " single argument to the app factory function in Flask"
-            " 2.1.",
-            DeprecationWarning,
-        )
-        args.append(script_info)
-
-    return app_factory(*args, **kwargs)
-
-
 def _called_with_wrong_args(f):
     """Check whether calling a function raised a ``TypeError`` because
     the call failed or because something in the factory raised the
@@ -145,7 +112,7 @@ def _called_with_wrong_args(f):
         del tb
 
 
-def find_app_by_string(script_info, module, app_name):
+def find_app_by_string(module, app_name):
     """Check if the given string is a variable name or a function. Call
     a function to get the app instance, or return the variable directly.
     """
@@ -158,11 +125,12 @@ def find_app_by_string(script_info, module, app_name):
     except SyntaxError:
         raise NoAppException(
             f"Failed to parse {app_name!r} as an attribute name or function call."
-        )
+        ) from None
 
     if isinstance(expr, ast.Name):
         name = expr.id
-        args = kwargs = None
+        args = []
+        kwargs = {}
     elif isinstance(expr, ast.Call):
         # Ensure the function name is an attribute name only.
         if not isinstance(expr.func, ast.Name):
@@ -181,7 +149,7 @@ def find_app_by_string(script_info, module, app_name):
             # message with the full expression instead.
             raise NoAppException(
                 f"Failed to parse arguments as literal values: {app_name!r}."
-            )
+            ) from None
     else:
         raise NoAppException(
             f"Failed to parse {app_name!r} as an attribute name or function call."
@@ -189,17 +157,17 @@ def find_app_by_string(script_info, module, app_name):
 
     try:
         attr = getattr(module, name)
-    except AttributeError:
+    except AttributeError as e:
         raise NoAppException(
             f"Failed to find attribute {name!r} in {module.__name__!r}."
-        )
+        ) from e
 
     # If the attribute is a function, call it with any args and kwargs
     # to get the real application.
     if inspect.isfunction(attr):
         try:
-            app = call_factory(script_info, attr, args, kwargs)
-        except TypeError:
+            app = attr(*args, **kwargs)
+        except TypeError as e:
             if not _called_with_wrong_args(attr):
                 raise
 
@@ -207,7 +175,7 @@ def find_app_by_string(script_info, module, app_name):
                 f"The factory {app_name!r} in module"
                 f" {module.__name__!r} could not be called with the"
                 " specified arguments."
-            )
+            ) from e
     else:
         app = attr
 
@@ -249,7 +217,7 @@ def prepare_import(path):
     return ".".join(module_name[::-1])
 
 
-def locate_app(script_info, module_name, app_name, raise_if_not_found=True):
+def locate_app(module_name, app_name, raise_if_not_found=True):
     __traceback_hide__ = True  # noqa: F841
 
     try:
@@ -261,18 +229,18 @@ def locate_app(script_info, module_name, app_name, raise_if_not_found=True):
             raise NoAppException(
                 f"While importing {module_name!r}, an ImportError was"
                 f" raised:\n\n{traceback.format_exc()}"
-            )
+            ) from None
         elif raise_if_not_found:
-            raise NoAppException(f"Could not import {module_name!r}.")
+            raise NoAppException(f"Could not import {module_name!r}.") from None
         else:
             return
 
     module = sys.modules[module_name]
 
     if app_name is None:
-        return find_best_app(script_info, module)
+        return find_best_app(module)
     else:
-        return find_app_by_string(script_info, module, app_name)
+        return find_app_by_string(module, app_name)
 
 
 def get_version(ctx, param, value):
@@ -312,7 +280,7 @@ class DispatchingApp:
         self.loader = loader
         self._app = None
         self._lock = Lock()
-        self._bg_loading_exc_info = None
+        self._bg_loading_exc = None
 
         if use_eager_loading is None:
             use_eager_loading = os.environ.get("WERKZEUG_RUN_MAIN") != "true"
@@ -328,23 +296,24 @@ class DispatchingApp:
             with self._lock:
                 try:
                     self._load_unlocked()
-                except Exception:
-                    self._bg_loading_exc_info = sys.exc_info()
+                except Exception as e:
+                    self._bg_loading_exc = e
 
         t = Thread(target=_load_app, args=())
         t.start()
 
     def _flush_bg_loading_exception(self):
         __traceback_hide__ = True  # noqa: F841
-        exc_info = self._bg_loading_exc_info
-        if exc_info is not None:
-            self._bg_loading_exc_info = None
-            raise exc_info
+        exc = self._bg_loading_exc
+
+        if exc is not None:
+            self._bg_loading_exc = None
+            raise exc
 
     def _load_unlocked(self):
         __traceback_hide__ = True  # noqa: F841
         self._app = rv = self.loader()
-        self._bg_loading_exc_info = None
+        self._bg_loading_exc = None
         return rv
 
     def __call__(self, environ, start_response):
@@ -392,18 +361,18 @@ class ScriptInfo:
             return self._loaded_app
 
         if self.create_app is not None:
-            app = call_factory(self, self.create_app)
+            app = self.create_app()
         else:
             if self.app_import_path:
                 path, name = (
                     re.split(r":(?![\\/])", self.app_import_path, 1) + [None]
                 )[:2]
                 import_name = prepare_import(path)
-                app = locate_app(self, import_name, name)
+                app = locate_app(import_name, name)
             else:
                 for path in ("wsgi.py", "app.py"):
                     import_name = prepare_import(path)
-                    app = locate_app(self, import_name, None, raise_if_not_found=False)
+                    app = locate_app(import_name, None, raise_if_not_found=False)
 
                     if app:
                         break
@@ -721,7 +690,7 @@ class CertParamType(click.ParamType):
                         "Using ad-hoc certificates requires the cryptography library.",
                         ctx,
                         param,
-                    )
+                    ) from None
 
                 return value
 
@@ -979,15 +948,7 @@ debug mode.
 
 
 def main() -> None:
-    if int(click.__version__[0]) < 8:
-        warnings.warn(
-            "Using the `flask` cli with Click 7 is deprecated and"
-            " will not be supported starting with Flask 2.1."
-            " Please upgrade to Click 8 as soon as possible.",
-            DeprecationWarning,
-        )
-    # TODO omit sys.argv once https://github.com/pallets/click/issues/536 is fixed
-    cli.main(args=sys.argv[1:])
+    cli.main()
 
 
 if __name__ == "__main__":
diff --git a/src/flask/config.py b/src/flask/config.py
index c79a558e..9657edc8 100644
--- a/src/flask/config.py
+++ b/src/flask/config.py
@@ -83,7 +83,7 @@ class Config(dict):
         :param variable_name: name of the environment variable
         :param silent: set to ``True`` if you want silent failure for missing
                        files.
-        :return: bool. ``True`` if able to load config, ``False`` otherwise.
+        :return: ``True`` if the file was loaded successfully.
         """
         rv = os.environ.get(variable_name)
         if not rv:
@@ -107,6 +107,7 @@ class Config(dict):
                          root path.
         :param silent: set to ``True`` if you want silent failure for missing
                        files.
+        :return: ``True`` if the file was loaded successfully.
 
         .. versionadded:: 0.7
            `silent` parameter.
@@ -175,6 +176,9 @@ class Config(dict):
 
         .. code-block:: python
 
+            import json
+            app.config.from_file("config.json", load=json.load)
+
             import toml
             app.config.from_file("config.toml", load=toml.load)
 
@@ -185,6 +189,7 @@ class Config(dict):
         :type load: ``Callable[[Reader], Mapping]`` where ``Reader``
             implements a ``read`` method.
         :param silent: Ignore the file if it doesn't exist.
+        :return: ``True`` if the file was loaded successfully.
 
         .. versionadded:: 2.0
         """
@@ -202,36 +207,12 @@ class Config(dict):
 
         return self.from_mapping(obj)
 
-    def from_json(self, filename: str, silent: bool = False) -> bool:
-        """Update the values in the config from a JSON file. The loaded
-        data is passed to the :meth:`from_mapping` method.
-
-        :param filename: The path to the JSON file. This can be an
-            absolute path or relative to the config root path.
-        :param silent: Ignore the file if it doesn't exist.
-
-        .. deprecated:: 2.0.0
-            Will be removed in Flask 2.1. Use :meth:`from_file` instead.
-            This was removed early in 2.0.0, was added back in 2.0.1.
-
-        .. versionadded:: 0.11
-        """
-        import warnings
-        from . import json
-
-        warnings.warn(
-            "'from_json' is deprecated and will be removed in Flask"
-            " 2.1. Use 'from_file(path, json.load)' instead.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-        return self.from_file(filename, json.load, silent=silent)
-
     def from_mapping(
         self, mapping: t.Optional[t.Mapping[str, t.Any]] = None, **kwargs: t.Any
     ) -> bool:
         """Updates the config like :meth:`update` ignoring items with non-upper
         keys.
+        :return: Always returns ``True``.
 
         .. versionadded:: 0.11
         """
diff --git a/src/flask/ctx.py b/src/flask/ctx.py
index 5c064635..b3687ba7 100644
--- a/src/flask/ctx.py
+++ b/src/flask/ctx.py
@@ -130,7 +130,15 @@ def after_this_request(f: AfterRequestCallable) -> AfterRequestCallable:
 
     .. versionadded:: 0.9
     """
-    _request_ctx_stack.top._after_request_functions.append(f)
+    top = _request_ctx_stack.top
+
+    if top is None:
+        raise RuntimeError(
+            "This decorator can only be used when a request context is"
+            " active, such as within a view function."
+        )
+
+    top._after_request_functions.append(f)
     return f
 
 
@@ -159,17 +167,18 @@ def copy_current_request_context(f: t.Callable) -> t.Callable:
     .. versionadded:: 0.10
     """
     top = _request_ctx_stack.top
+
     if top is None:
         raise RuntimeError(
-            "This decorator can only be used at local scopes "
-            "when a request context is on the stack.  For instance within "
-            "view functions."
+            "This decorator can only be used when a request context is"
+            " active, such as within a view function."
         )
+
     reqctx = top.copy()
 
     def wrapper(*args, **kwargs):
         with reqctx:
-            return f(*args, **kwargs)
+            return reqctx.app.ensure_sync(f)(*args, **kwargs)
 
     return update_wrapper(wrapper, f)
 
@@ -332,11 +341,29 @@ class RequestContext:
         self._after_request_functions: t.List[AfterRequestCallable] = []
 
     @property
-    def g(self) -> AppContext:
+    def g(self) -> _AppCtxGlobals:
+        import warnings
+
+        warnings.warn(
+            "Accessing 'g' on the request context is deprecated and"
+            " will be removed in Flask 2.2. Access `g` directly or from"
+            "the application context instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         return _app_ctx_stack.top.g
 
     @g.setter
-    def g(self, value: AppContext) -> None:
+    def g(self, value: _AppCtxGlobals) -> None:
+        import warnings
+
+        warnings.warn(
+            "Setting 'g' on the request context is deprecated and"
+            " will be removed in Flask 2.2. Set it on the application"
+            " context instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
         _app_ctx_stack.top.g = value
 
     def copy(self) -> "RequestContext":
diff --git a/src/flask/debughelpers.py b/src/flask/debughelpers.py
index ce65c487..212f7d7e 100644
--- a/src/flask/debughelpers.py
+++ b/src/flask/debughelpers.py
@@ -83,10 +83,11 @@ def attach_enctype_error_multidict(request):
         def __getitem__(self, key):
             try:
                 return oldcls.__getitem__(self, key)
-            except KeyError:
+            except KeyError as e:
                 if key not in request.form:
                     raise
-                raise DebugFilesKeyError(request, key)
+
+                raise DebugFilesKeyError(request, key) from e
 
     newcls.__name__ = oldcls.__name__
     newcls.__module__ = oldcls.__module__
diff --git a/src/flask/helpers.py b/src/flask/helpers.py
index 7b8b0870..84059319 100644
--- a/src/flask/helpers.py
+++ b/src/flask/helpers.py
@@ -5,13 +5,11 @@ import sys
 import typing as t
 import warnings
 from datetime import datetime
-from datetime import timedelta
 from functools import lru_cache
 from functools import update_wrapper
 from threading import RLock
 
 import werkzeug.utils
-from werkzeug.exceptions import NotFound
 from werkzeug.routing import BuildError
 from werkzeug.urls import url_quote
 
@@ -454,7 +452,7 @@ def _prepare_send_file_kwargs(
         warnings.warn(
             "The 'attachment_filename' parameter has been renamed to"
             " 'download_name'. The old name will be removed in Flask"
-            " 2.1.",
+            " 2.2.",
             DeprecationWarning,
             stacklevel=3,
         )
@@ -463,7 +461,7 @@ def _prepare_send_file_kwargs(
     if cache_timeout is not None:
         warnings.warn(
             "The 'cache_timeout' parameter has been renamed to"
-            " 'max_age'. The old name will be removed in Flask 2.1.",
+            " 'max_age'. The old name will be removed in Flask 2.2.",
             DeprecationWarning,
             stacklevel=3,
         )
@@ -472,7 +470,7 @@ def _prepare_send_file_kwargs(
     if add_etags is not None:
         warnings.warn(
             "The 'add_etags' parameter has been renamed to 'etag'. The"
-            " old name will be removed in Flask 2.1.",
+            " old name will be removed in Flask 2.2.",
             DeprecationWarning,
             stacklevel=3,
         )
@@ -627,29 +625,6 @@ def send_file(
     )
 
 
-def safe_join(directory: str, *pathnames: str) -> str:
-    """Safely join zero or more untrusted path components to a base
-    directory to avoid escaping the base directory.
-
-    :param directory: The trusted base directory.
-    :param pathnames: The untrusted path components relative to the
-        base directory.
-    :return: A safe path, otherwise ``None``.
-    """
-    warnings.warn(
-        "'flask.helpers.safe_join' is deprecated and will be removed in"
-        " Flask 2.1. Use 'werkzeug.utils.safe_join' instead.",
-        DeprecationWarning,
-        stacklevel=2,
-    )
-    path = werkzeug.utils.safe_join(directory, *pathnames)
-
-    if path is None:
-        raise NotFound()
-
-    return path
-
-
 def send_from_directory(
     directory: t.Union[os.PathLike, str],
     path: t.Union[os.PathLike, str],
@@ -691,7 +666,7 @@ def send_from_directory(
     if filename is not None:
         warnings.warn(
             "The 'filename' parameter has been renamed to 'path'. The"
-            " old name will be removed in Flask 2.1.",
+            " old name will be removed in Flask 2.2.",
             DeprecationWarning,
             stacklevel=2,
         )
@@ -714,7 +689,7 @@ def get_root_path(import_name: str) -> str:
     # Module already imported and has a file attribute. Use that first.
     mod = sys.modules.get(import_name)
 
-    if mod is not None and hasattr(mod, "__file__"):
+    if mod is not None and hasattr(mod, "__file__") and mod.__file__ is not None:
         return os.path.dirname(os.path.abspath(mod.__file__))
 
     # Next attempt: check the loader.
@@ -785,27 +760,6 @@ class locked_cached_property(werkzeug.utils.cached_property):
             super().__delete__(obj)
 
 
-def total_seconds(td: timedelta) -> int:
-    """Returns the total seconds from a timedelta object.
-
-    :param timedelta td: the timedelta to be converted in seconds
-
-    :returns: number of seconds
-    :rtype: int
-
-    .. deprecated:: 2.0
-        Will be removed in Flask 2.1. Use
-        :meth:`timedelta.total_seconds` instead.
-    """
-    warnings.warn(
-        "'total_seconds' is deprecated and will be removed in Flask"
-        " 2.1. Use 'timedelta.total_seconds' instead.",
-        DeprecationWarning,
-        stacklevel=2,
-    )
-    return td.days * 60 * 60 * 24 + td.seconds
-
-
 def is_ip(value: str) -> bool:
     """Determine if the given string is an IP address.
 
diff --git a/src/flask/json/__init__.py b/src/flask/json/__init__.py
index 5780e204..43c018e7 100644
--- a/src/flask/json/__init__.py
+++ b/src/flask/json/__init__.py
@@ -1,8 +1,8 @@
-import io
+import dataclasses
+import decimal
 import json as _json
 import typing as t
 import uuid
-import warnings
 from datetime import date
 
 from jinja2.utils import htmlsafe_json_dumps as _jinja_htmlsafe_dumps
@@ -15,12 +15,6 @@ if t.TYPE_CHECKING:
     from ..app import Flask
     from ..wrappers import Response
 
-try:
-    import dataclasses
-except ImportError:
-    # Python < 3.7
-    dataclasses = None  # type: ignore
-
 
 class JSONEncoder(_json.JSONEncoder):
     """The default JSON encoder. Handles extra types compared to the
@@ -47,7 +41,7 @@ class JSONEncoder(_json.JSONEncoder):
         """
         if isinstance(o, date):
             return http_date(o)
-        if isinstance(o, uuid.UUID):
+        if isinstance(o, (decimal.Decimal, uuid.UUID)):
             return str(o)
         if dataclasses and dataclasses.is_dataclass(o):
             return dataclasses.asdict(o)
@@ -80,6 +74,11 @@ def _dump_arg_defaults(
         if bp is not None and bp.json_encoder is not None:
             cls = bp.json_encoder
 
+        # Only set a custom encoder if it has custom behavior. This is
+        # faster on PyPy.
+        if cls is not _json.JSONEncoder:
+            kwargs.setdefault("cls", cls)
+
         kwargs.setdefault("cls", cls)
         kwargs.setdefault("ensure_ascii", app.config["JSON_AS_ASCII"])
         kwargs.setdefault("sort_keys", app.config["JSON_SORT_KEYS"])
@@ -101,9 +100,10 @@ def _load_arg_defaults(
         if bp is not None and bp.json_decoder is not None:
             cls = bp.json_decoder
 
-        kwargs.setdefault("cls", cls)
-    else:
-        kwargs.setdefault("cls", JSONDecoder)
+        # Only set a custom decoder if it has custom behavior. This is
+        # faster on PyPy.
+        if cls not in {JSONDecoder, _json.JSONDecoder}:
+            kwargs.setdefault("cls", cls)
 
 
 def dumps(obj: t.Any, app: t.Optional["Flask"] = None, **kwargs: t.Any) -> str:
@@ -117,6 +117,9 @@ def dumps(obj: t.Any, app: t.Optional["Flask"] = None, **kwargs: t.Any) -> str:
         or defaults.
     :param kwargs: Extra arguments passed to :func:`json.dumps`.
 
+    .. versionchanged:: 2.0.2
+        :class:`decimal.Decimal` is supported by converting to a string.
+
     .. versionchanged:: 2.0
         ``encoding`` is deprecated and will be removed in Flask 2.1.
 
@@ -125,20 +128,7 @@ def dumps(obj: t.Any, app: t.Optional["Flask"] = None, **kwargs: t.Any) -> str:
         context for configuration.
     """
     _dump_arg_defaults(kwargs, app=app)
-    encoding = kwargs.pop("encoding", None)
-    rv = _json.dumps(obj, **kwargs)
-
-    if encoding is not None:
-        warnings.warn(
-            "'encoding' is deprecated and will be removed in Flask 2.1.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-
-        if isinstance(rv, str):
-            return rv.encode(encoding)  # type: ignore
-
-    return rv
+    return _json.dumps(obj, **kwargs)
 
 
 def dump(
@@ -160,23 +150,6 @@ def dump(
         deprecated and will be removed in Flask 2.1.
     """
     _dump_arg_defaults(kwargs, app=app)
-    encoding = kwargs.pop("encoding", None)
-    show_warning = encoding is not None
-
-    try:
-        fp.write("")
-    except TypeError:
-        show_warning = True
-        fp = io.TextIOWrapper(fp, encoding or "utf-8")  # type: ignore
-
-    if show_warning:
-        warnings.warn(
-            "Writing to a binary file, and the 'encoding' argument, is"
-            " deprecated and will be removed in Flask 2.1.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-
     _json.dump(obj, fp, **kwargs)
 
 
@@ -200,19 +173,6 @@ def loads(s: str, app: t.Optional["Flask"] = None, **kwargs: t.Any) -> t.Any:
         context for configuration.
     """
     _load_arg_defaults(kwargs, app=app)
-    encoding = kwargs.pop("encoding", None)
-
-    if encoding is not None:
-        warnings.warn(
-            "'encoding' is deprecated and will be removed in Flask 2.1."
-            " The data must be a string or UTF-8 bytes.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-
-        if isinstance(s, bytes):
-            s = s.decode(encoding)
-
     return _json.loads(s, **kwargs)
 
 
@@ -232,20 +192,6 @@ def load(fp: t.IO[str], app: t.Optional["Flask"] = None, **kwargs: t.Any) -> t.A
         file must be text mode, or binary mode with UTF-8 bytes.
     """
     _load_arg_defaults(kwargs, app=app)
-    encoding = kwargs.pop("encoding", None)
-
-    if encoding is not None:
-        warnings.warn(
-            "'encoding' is deprecated and will be removed in Flask 2.1."
-            " The file must be text mode, or binary mode with UTF-8"
-            " bytes.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-
-        if isinstance(fp.read(0), bytes):
-            fp = io.TextIOWrapper(fp, encoding)  # type: ignore
-
     return _json.load(fp, **kwargs)
 
 
@@ -324,6 +270,9 @@ def jsonify(*args: t.Any, **kwargs: t.Any) -> "Response":
     debug mode or if :data:`JSONIFY_PRETTYPRINT_REGULAR` is ``True``,
     the output will be formatted to be easier to read.
 
+    .. versionchanged:: 2.0.2
+        :class:`decimal.Decimal` is supported by converting to a string.
+
     .. versionchanged:: 0.11
         Added support for serializing top-level arrays. This introduces
         a security risk in ancient browsers. See :ref:`security-json`.
diff --git a/src/flask/scaffold.py b/src/flask/scaffold.py
index 239bc46a..1cf007e2 100644
--- a/src/flask/scaffold.py
+++ b/src/flask/scaffold.py
@@ -21,7 +21,7 @@ from .templating import _default_template_ctx_processor
 from .typing import AfterRequestCallable
 from .typing import AppOrBlueprintKey
 from .typing import BeforeRequestCallable
-from .typing import ErrorHandlerCallable
+from .typing import GenericException
 from .typing import TeardownCallable
 from .typing import TemplateContextProcessorCallable
 from .typing import URLDefaultCallable
@@ -29,6 +29,7 @@ from .typing import URLValuePreprocessorCallable
 
 if t.TYPE_CHECKING:
     from .wrappers import Response
+    from .typing import ErrorHandlerCallable
 
 # a singleton sentinel value for parameter defaults
 _sentinel = object()
@@ -91,7 +92,7 @@ class Scaffold:
     def __init__(
         self,
         import_name: str,
-        static_folder: t.Optional[str] = None,
+        static_folder: t.Optional[t.Union[str, os.PathLike]] = None,
         static_url_path: t.Optional[str] = None,
         template_folder: t.Optional[str] = None,
         root_path: t.Optional[str] = None,
@@ -100,7 +101,7 @@ class Scaffold:
         #: to. Do not change this once it is set by the constructor.
         self.import_name = import_name
 
-        self.static_folder = static_folder
+        self.static_folder = static_folder  # type: ignore
         self.static_url_path = static_url_path
 
         #: The path to the templates folder, relative to
@@ -144,7 +145,10 @@ class Scaffold:
         #: directly and its format may change at any time.
         self.error_handler_spec: t.Dict[
             AppOrBlueprintKey,
-            t.Dict[t.Optional[int], t.Dict[t.Type[Exception], ErrorHandlerCallable]],
+            t.Dict[
+                t.Optional[int],
+                t.Dict[t.Type[Exception], "ErrorHandlerCallable[Exception]"],
+            ],
         ] = defaultdict(lambda: defaultdict(dict))
 
         #: A data structure of functions to call at the beginning of
@@ -253,7 +257,7 @@ class Scaffold:
             return None
 
     @static_folder.setter
-    def static_folder(self, value: t.Optional[str]) -> None:
+    def static_folder(self, value: t.Optional[t.Union[str, os.PathLike]]) -> None:
         if value is not None:
             value = os.fspath(value).rstrip(r"\/")
 
@@ -585,10 +589,10 @@ class Scaffold:
         stack of active contexts.  This becomes relevant if you are using
         such constructs in tests.
 
-        Teardown functions must avoid raising exceptions, since they . If they
-        execute code that might fail they
-        will have to surround the execution of these code by try/except
-        statements and log occurring errors.
+        Teardown functions must avoid raising exceptions. If
+        they execute code that might fail they
+        will have to surround the execution of that code with try/except
+        statements and log any errors.
 
         When a teardown function was called because of an exception it will
         be passed an error object.
@@ -643,8 +647,11 @@ class Scaffold:
 
     @setupmethod
     def errorhandler(
-        self, code_or_exception: t.Union[t.Type[Exception], int]
-    ) -> t.Callable[[ErrorHandlerCallable], ErrorHandlerCallable]:
+        self, code_or_exception: t.Union[t.Type[GenericException], int]
+    ) -> t.Callable[
+        ["ErrorHandlerCallable[GenericException]"],
+        "ErrorHandlerCallable[GenericException]",
+    ]:
         """Register a function to handle errors by code or exception class.
 
         A decorator that is used to register a function given an
@@ -674,7 +681,9 @@ class Scaffold:
                                   an arbitrary exception
         """
 
-        def decorator(f: ErrorHandlerCallable) -> ErrorHandlerCallable:
+        def decorator(
+            f: "ErrorHandlerCallable[GenericException]",
+        ) -> "ErrorHandlerCallable[GenericException]":
             self.register_error_handler(code_or_exception, f)
             return f
 
@@ -683,8 +692,8 @@ class Scaffold:
     @setupmethod
     def register_error_handler(
         self,
-        code_or_exception: t.Union[t.Type[Exception], int],
-        f: ErrorHandlerCallable,
+        code_or_exception: t.Union[t.Type[GenericException], int],
+        f: "ErrorHandlerCallable[GenericException]",
     ) -> None:
         """Alternative error attach function to the :meth:`errorhandler`
         decorator that is more straightforward to use for non decorator
@@ -706,9 +715,11 @@ class Scaffold:
                 f"'{code_or_exception}' is not a recognized HTTP error"
                 " code. Use a subclass of HTTPException with that code"
                 " instead."
-            )
+            ) from None
 
-        self.error_handler_spec[None][code][exc_class] = f
+        self.error_handler_spec[None][code][exc_class] = t.cast(
+            "ErrorHandlerCallable[Exception]", f
+        )
 
     @staticmethod
     def _get_exc_class_and_code(
diff --git a/src/flask/sessions.py b/src/flask/sessions.py
index 34b1d0ce..20648dea 100644
--- a/src/flask/sessions.py
+++ b/src/flask/sessions.py
@@ -131,6 +131,13 @@ class SessionInterface:
         app = Flask(__name__)
         app.session_interface = MySessionInterface()
 
+    Multiple requests with the same session may be sent and handled
+    concurrently. When implementing a new session interface, consider
+    whether reads or writes to the backing store must be synchronized.
+    There is no guarantee on the order in which the session for each
+    request is opened or saved, it will occur in the order that requests
+    begin and end processing.
+
     .. versionadded:: 0.8
     """
 
@@ -292,20 +299,25 @@ class SessionInterface:
     def open_session(
         self, app: "Flask", request: "Request"
     ) -> t.Optional[SessionMixin]:
-        """This method has to be implemented and must either return ``None``
-        in case the loading failed because of a configuration error or an
-        instance of a session object which implements a dictionary like
-        interface + the methods and attributes on :class:`SessionMixin`.
+        """This is called at the beginning of each request, after
+        pushing the request context, before matching the URL.
+
+        This must return an object which implements a dictionary-like
+        interface as well as the :class:`SessionMixin` interface.
+
+        This will return ``None`` to indicate that loading failed in
+        some way that is not immediately an error. The request
+        context will fall back to using :meth:`make_null_session`
+        in this case.
         """
         raise NotImplementedError()
 
     def save_session(
         self, app: "Flask", session: SessionMixin, response: "Response"
     ) -> None:
-        """This is called for actual sessions returned by :meth:`open_session`
-        at the end of the request.  This is still called during a request
-        context so if you absolutely need access to the request you can do
-        that.
+        """This is called at the end of each request, after generating
+        a response, before removing the request context. It is skipped
+        if :meth:`is_null_session` returns ``True``.
         """
         raise NotImplementedError()
 
diff --git a/src/flask/signals.py b/src/flask/signals.py
index 63667bdb..2c6d6469 100644
--- a/src/flask/signals.py
+++ b/src/flask/signals.py
@@ -29,7 +29,7 @@ except ImportError:
             raise RuntimeError(
                 "Signalling support is unavailable because the blinker"
                 " library is not installed."
-            )
+            ) from None
 
         connect = connect_via = connected_to = temporarily_connected_to = _fail
         disconnect = _fail
diff --git a/src/flask/testing.py b/src/flask/testing.py
index fe3b846a..1b35cc7a 100644
--- a/src/flask/testing.py
+++ b/src/flask/testing.py
@@ -9,14 +9,15 @@ from werkzeug.test import Client
 from werkzeug.urls import url_parse
 from werkzeug.wrappers import Request as BaseRequest
 
-from . import _request_ctx_stack
 from .cli import ScriptInfo
+from .globals import _request_ctx_stack
 from .json import dumps as json_dumps
 from .sessions import SessionMixin
 
 if t.TYPE_CHECKING:
+    from werkzeug.test import TestResponse
+
     from .app import Flask
-    from .wrappers import Response
 
 
 class EnvironBuilder(werkzeug.test.EnvironBuilder):
@@ -171,14 +172,15 @@ class FlaskClient(Client):
             headers = resp.get_wsgi_headers(c.request.environ)
             self.cookie_jar.extract_wsgi(c.request.environ, headers)
 
-    def open(  # type: ignore
+    def open(
         self,
         *args: t.Any,
-        as_tuple: bool = False,
         buffered: bool = False,
         follow_redirects: bool = False,
         **kwargs: t.Any,
-    ) -> "Response":
+    ) -> "TestResponse":
+        as_tuple = kwargs.pop("as_tuple", None)
+
         # Same logic as super.open, but apply environ_base and preserve_context.
         request = None
 
@@ -213,12 +215,28 @@ class FlaskClient(Client):
             finally:
                 builder.close()
 
-        return super().open(  # type: ignore
-            request,
-            as_tuple=as_tuple,
-            buffered=buffered,
-            follow_redirects=follow_redirects,
-        )
+        if as_tuple is not None:
+            import warnings
+
+            warnings.warn(
+                "'as_tuple' is deprecated and will be removed in"
+                " Werkzeug 2.1 and Flask 2.1. Use"
+                " 'response.request.environ' instead.",
+                DeprecationWarning,
+                stacklevel=3,
+            )
+            return super().open(
+                request,
+                as_tuple=as_tuple,
+                buffered=buffered,
+                follow_redirects=follow_redirects,
+            )
+        else:
+            return super().open(
+                request,
+                buffered=buffered,
+                follow_redirects=follow_redirects,
+            )
 
     def __enter__(self) -> "FlaskClient":
         if self.preserve_context:
@@ -272,7 +290,7 @@ class FlaskCliRunner(CliRunner):
         :return: a :class:`~click.testing.Result` object.
         """
         if cli is None:
-            cli = self.app.cli
+            cli = self.app.cli  # type: ignore
 
         if "obj" not in kwargs:
             kwargs["obj"] = ScriptInfo(create_app=lambda: self.app)
diff --git a/src/flask/typing.py b/src/flask/typing.py
index b1a6cbdc..93896f80 100644
--- a/src/flask/typing.py
+++ b/src/flask/typing.py
@@ -33,11 +33,12 @@ ResponseReturnValue = t.Union[
     "WSGIApplication",
 ]
 
+GenericException = t.TypeVar("GenericException", bound=Exception, contravariant=True)
+
 AppOrBlueprintKey = t.Optional[str]  # The App key is None, whereas blueprints are named
 AfterRequestCallable = t.Callable[["Response"], "Response"]
 BeforeFirstRequestCallable = t.Callable[[], None]
 BeforeRequestCallable = t.Callable[[], t.Optional[ResponseReturnValue]]
-ErrorHandlerCallable = t.Callable[[Exception], ResponseReturnValue]
 TeardownCallable = t.Callable[[t.Optional[BaseException]], None]
 TemplateContextProcessorCallable = t.Callable[[], t.Dict[str, t.Any]]
 TemplateFilterCallable = t.Callable[..., t.Any]
@@ -45,3 +46,4 @@ TemplateGlobalCallable = t.Callable[..., t.Any]
 TemplateTestCallable = t.Callable[..., bool]
 URLDefaultCallable = t.Callable[[str, dict], None]
 URLValuePreprocessorCallable = t.Callable[[t.Optional[str], t.Optional[dict]], None]
+ErrorHandlerCallable = t.Callable[[GenericException], ResponseReturnValue]
diff --git a/src/flask/views.py b/src/flask/views.py
index 339ffa18..1bd5c68b 100644
--- a/src/flask/views.py
+++ b/src/flask/views.py
@@ -1,5 +1,6 @@
 import typing as t
 
+from .globals import current_app
 from .globals import request
 from .typing import ResponseReturnValue
 
@@ -80,7 +81,7 @@ class View:
 
         def view(*args: t.Any, **kwargs: t.Any) -> ResponseReturnValue:
             self = view.view_class(*class_args, **class_kwargs)  # type: ignore
-            return self.dispatch_request(*args, **kwargs)
+            return current_app.ensure_sync(self.dispatch_request)(*args, **kwargs)
 
         if cls.decorators:
             view.__name__ = name
@@ -154,4 +155,4 @@ class MethodView(View, metaclass=MethodViewType):
             meth = getattr(self, "get", None)
 
         assert meth is not None, f"Unimplemented method {request.method!r}"
-        return meth(*args, **kwargs)
+        return current_app.ensure_sync(meth)(*args, **kwargs)
diff --git a/tests/test_async.py b/tests/test_async.py
index 26a91118..c8bb9bf0 100644
--- a/tests/test_async.py
+++ b/tests/test_async.py
@@ -1,11 +1,12 @@
 import asyncio
-import sys
 
 import pytest
 
 from flask import Blueprint
 from flask import Flask
 from flask import request
+from flask.views import MethodView
+from flask.views import View
 
 pytest.importorskip("asgiref")
 
@@ -18,6 +19,24 @@ class BlueprintError(Exception):
     pass
 
 
+class AsyncView(View):
+    methods = ["GET", "POST"]
+
+    async def dispatch_request(self):
+        await asyncio.sleep(0)
+        return request.method
+
+
+class AsyncMethodView(MethodView):
+    async def get(self):
+        await asyncio.sleep(0)
+        return "GET"
+
+    async def post(self):
+        await asyncio.sleep(0)
+        return "POST"
+
+
 @pytest.fixture(name="async_app")
 def _async_app():
     app = Flask(__name__)
@@ -53,11 +72,13 @@ def _async_app():
 
     app.register_blueprint(blueprint, url_prefix="/bp")
 
+    app.add_url_rule("/view", view_func=AsyncView.as_view("view"))
+    app.add_url_rule("/methodview", view_func=AsyncMethodView.as_view("methodview"))
+
     return app
 
 
-@pytest.mark.skipif(sys.version_info < (3, 7), reason="requires Python >= 3.7")
-@pytest.mark.parametrize("path", ["/", "/home", "/bp/"])
+@pytest.mark.parametrize("path", ["/", "/home", "/bp/", "/view", "/methodview"])
 def test_async_route(path, async_app):
     test_client = async_app.test_client()
     response = test_client.get(path)
@@ -66,7 +87,6 @@ def test_async_route(path, async_app):
     assert b"POST" in response.get_data()
 
 
-@pytest.mark.skipif(sys.version_info < (3, 7), reason="requires Python >= 3.7")
 @pytest.mark.parametrize("path", ["/error", "/bp/error"])
 def test_async_error_handler(path, async_app):
     test_client = async_app.test_client()
@@ -74,7 +94,6 @@ def test_async_error_handler(path, async_app):
     assert response.status_code == 412
 
 
-@pytest.mark.skipif(sys.version_info < (3, 7), reason="requires Python >= 3.7")
 def test_async_before_after_request():
     app_first_called = False
     app_before_called = False
@@ -131,10 +150,3 @@ def test_async_before_after_request():
     test_client.get("/bp/")
     assert bp_before_called
     assert bp_after_called
-
-
-@pytest.mark.skipif(sys.version_info >= (3, 7), reason="should only raise Python < 3.7")
-def test_async_runtime_error():
-    app = Flask(__name__)
-    with pytest.raises(RuntimeError):
-        app.async_to_sync(None)
diff --git a/tests/test_basic.py b/tests/test_basic.py
index 2cb96794..ce85ee71 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -1,6 +1,5 @@
 import gc
 import re
-import sys
 import time
 import uuid
 import weakref
@@ -1323,7 +1322,6 @@ def test_jsonify_mimetype(app, req_ctx):
     assert rv.mimetype == "application/vnd.api+json"
 
 
-@pytest.mark.skipif(sys.version_info < (3, 7), reason="requires Python >= 3.7")
 def test_json_dump_dataclass(app, req_ctx):
     from dataclasses import make_dataclass
 
diff --git a/tests/test_blueprints.py b/tests/test_blueprints.py
index 088ad779..fbe9eeee 100644
--- a/tests/test_blueprints.py
+++ b/tests/test_blueprints.py
@@ -837,6 +837,86 @@ def test_nested_blueprint(app, client):
     assert client.get("/parent/child/grandchild/no").data == b"Grandchild no"
 
 
+def test_nested_callback_order(app, client):
+    parent = flask.Blueprint("parent", __name__)
+    child = flask.Blueprint("child", __name__)
+
+    @app.before_request
+    def app_before1():
+        flask.g.setdefault("seen", []).append("app_1")
+
+    @app.teardown_request
+    def app_teardown1(e=None):
+        assert flask.g.seen.pop() == "app_1"
+
+    @app.before_request
+    def app_before2():
+        flask.g.setdefault("seen", []).append("app_2")
+
+    @app.teardown_request
+    def app_teardown2(e=None):
+        assert flask.g.seen.pop() == "app_2"
+
+    @app.context_processor
+    def app_ctx():
+        return dict(key="app")
+
+    @parent.before_request
+    def parent_before1():
+        flask.g.setdefault("seen", []).append("parent_1")
+
+    @parent.teardown_request
+    def parent_teardown1(e=None):
+        assert flask.g.seen.pop() == "parent_1"
+
+    @parent.before_request
+    def parent_before2():
+        flask.g.setdefault("seen", []).append("parent_2")
+
+    @parent.teardown_request
+    def parent_teardown2(e=None):
+        assert flask.g.seen.pop() == "parent_2"
+
+    @parent.context_processor
+    def parent_ctx():
+        return dict(key="parent")
+
+    @child.before_request
+    def child_before1():
+        flask.g.setdefault("seen", []).append("child_1")
+
+    @child.teardown_request
+    def child_teardown1(e=None):
+        assert flask.g.seen.pop() == "child_1"
+
+    @child.before_request
+    def child_before2():
+        flask.g.setdefault("seen", []).append("child_2")
+
+    @child.teardown_request
+    def child_teardown2(e=None):
+        assert flask.g.seen.pop() == "child_2"
+
+    @child.context_processor
+    def child_ctx():
+        return dict(key="child")
+
+    @child.route("/a")
+    def a():
+        return ", ".join(flask.g.seen)
+
+    @child.route("/b")
+    def b():
+        return flask.render_template_string("{{ key }}")
+
+    parent.register_blueprint(child)
+    app.register_blueprint(parent)
+    assert (
+        client.get("/a").data == b"app_1, app_2, parent_1, parent_2, child_1, child_2"
+    )
+    assert client.get("/b").data == b"child"
+
+
 @pytest.mark.parametrize(
     "parent_init, child_init, parent_registration, child_registration",
     [
@@ -874,8 +954,8 @@ def test_unique_blueprint_names(app, client) -> None:
 
     app.register_blueprint(bp)
 
-    with pytest.warns(UserWarning):
-        app.register_blueprint(bp)  # same bp, same name, warning
+    with pytest.raises(ValueError):
+        app.register_blueprint(bp)  # same bp, same name, error
 
     app.register_blueprint(bp, name="again")  # same bp, different name, ok
 
@@ -899,6 +979,14 @@ def test_blueprint_renaming(app, client) -> None:
     def index():
         return flask.request.endpoint
 
+    @bp.get("/error")
+    def error():
+        flask.abort(403)
+
+    @bp.errorhandler(403)
+    def forbidden(_: Exception):
+        return "Error", 403
+
     @bp2.get("/")
     def index2():
         return flask.request.endpoint
@@ -911,3 +999,5 @@ def test_blueprint_renaming(app, client) -> None:
     assert client.get("/b/").data == b"alt.index"
     assert client.get("/a/a/").data == b"bp.sub.index2"
     assert client.get("/b/a/").data == b"alt.sub.index2"
+    assert client.get("/a/error").data == b"Error"
+    assert client.get("/b/error").data == b"Error"
diff --git a/tests/test_cli.py b/tests/test_cli.py
index ebf8d1f5..a2fcc5a1 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1,6 +1,7 @@
 # This file was part of Flask-CLI and was modified under the terms of
 # its Revised BSD License. Copyright © 2015 CERN.
 import os
+import platform
 import ssl
 import sys
 import types
@@ -17,6 +18,7 @@ from flask import Blueprint
 from flask import current_app
 from flask import Flask
 from flask.cli import AppGroup
+from flask.cli import DispatchingApp
 from flask.cli import dotenv
 from flask.cli import find_best_app
 from flask.cli import FlaskGroup
@@ -47,51 +49,36 @@ def test_cli_name(test_apps):
 
 
 def test_find_best_app(test_apps):
-    script_info = ScriptInfo()
-
     class Module:
         app = Flask("appname")
 
-    assert find_best_app(script_info, Module) == Module.app
+    assert find_best_app(Module) == Module.app
 
     class Module:
         application = Flask("appname")
 
-    assert find_best_app(script_info, Module) == Module.application
+    assert find_best_app(Module) == Module.application
 
     class Module:
         myapp = Flask("appname")
 
-    assert find_best_app(script_info, Module) == Module.myapp
+    assert find_best_app(Module) == Module.myapp
 
     class Module:
         @staticmethod
         def create_app():
             return Flask("appname")
 
-    app = find_best_app(script_info, Module)
+    app = find_best_app(Module)
     assert isinstance(app, Flask)
     assert app.name == "appname"
 
     class Module:
         @staticmethod
-        def create_app(foo):
+        def create_app(**kwargs):
             return Flask("appname")
 
-    with pytest.deprecated_call(match="Script info"):
-        app = find_best_app(script_info, Module)
-
-    assert isinstance(app, Flask)
-    assert app.name == "appname"
-
-    class Module:
-        @staticmethod
-        def create_app(foo=None, script_info=None):
-            return Flask("appname")
-
-    with pytest.deprecated_call(match="script_info"):
-        app = find_best_app(script_info, Module)
-
+    app = find_best_app(Module)
     assert isinstance(app, Flask)
     assert app.name == "appname"
 
@@ -100,7 +87,7 @@ def test_find_best_app(test_apps):
         def make_app():
             return Flask("appname")
 
-    app = find_best_app(script_info, Module)
+    app = find_best_app(Module)
     assert isinstance(app, Flask)
     assert app.name == "appname"
 
@@ -111,7 +98,7 @@ def test_find_best_app(test_apps):
         def create_app():
             return Flask("appname2")
 
-    assert find_best_app(script_info, Module) == Module.myapp
+    assert find_best_app(Module) == Module.myapp
 
     class Module:
         myapp = Flask("appname1")
@@ -120,32 +107,32 @@ def test_find_best_app(test_apps):
         def create_app():
             return Flask("appname2")
 
-    assert find_best_app(script_info, Module) == Module.myapp
+    assert find_best_app(Module) == Module.myapp
 
     class Module:
         pass
 
-    pytest.raises(NoAppException, find_best_app, script_info, Module)
+    pytest.raises(NoAppException, find_best_app, Module)
 
     class Module:
         myapp1 = Flask("appname1")
         myapp2 = Flask("appname2")
 
-    pytest.raises(NoAppException, find_best_app, script_info, Module)
+    pytest.raises(NoAppException, find_best_app, Module)
 
     class Module:
         @staticmethod
         def create_app(foo, bar):
             return Flask("appname2")
 
-    pytest.raises(NoAppException, find_best_app, script_info, Module)
+    pytest.raises(NoAppException, find_best_app, Module)
 
     class Module:
         @staticmethod
         def create_app():
             raise TypeError("bad bad factory!")
 
-    pytest.raises(TypeError, find_best_app, script_info, Module)
+    pytest.raises(TypeError, find_best_app, Module)
 
 
 @pytest.mark.parametrize(
@@ -209,8 +196,7 @@ def test_prepare_import(request, value, path, result):
     ),
 )
 def test_locate_app(test_apps, iname, aname, result):
-    info = ScriptInfo()
-    assert locate_app(info, iname, aname).name == result
+    assert locate_app(iname, aname).name == result
 
 
 @pytest.mark.parametrize(
@@ -232,20 +218,17 @@ def test_locate_app(test_apps, iname, aname, result):
     ),
 )
 def test_locate_app_raises(test_apps, iname, aname):
-    info = ScriptInfo()
-
     with pytest.raises(NoAppException):
-        locate_app(info, iname, aname)
+        locate_app(iname, aname)
 
 
 def test_locate_app_suppress_raise(test_apps):
-    info = ScriptInfo()
-    app = locate_app(info, "notanapp.py", None, raise_if_not_found=False)
+    app = locate_app("notanapp.py", None, raise_if_not_found=False)
     assert app is None
 
     # only direct import error is suppressed
     with pytest.raises(NoAppException):
-        locate_app(info, "cliapp.importerrorapp", None, raise_if_not_found=False)
+        locate_app("cliapp.importerrorapp", None, raise_if_not_found=False)
 
 
 def test_get_version(test_apps, capsys):
@@ -310,6 +293,26 @@ def test_scriptinfo(test_apps, monkeypatch):
     assert app.name == "testapp"
 
 
+@pytest.mark.xfail(platform.python_implementation() == "PyPy", reason="flaky on pypy")
+def test_lazy_load_error(monkeypatch):
+    """When using lazy loading, the correct exception should be
+    re-raised.
+    """
+
+    class BadExc(Exception):
+        pass
+
+    def bad_load():
+        raise BadExc
+
+    lazy = DispatchingApp(bad_load, use_eager_loading=False)
+
+    with pytest.raises(BadExc):
+        # reduce flakiness by waiting for the internal loading lock
+        with lazy._lock:
+            lazy._flush_bg_loading_exception()
+
+
 def test_with_appcontext(runner):
     @click.command()
     @with_appcontext
diff --git a/tests/test_json.py b/tests/test_json.py
index fb8bdcba..9210275a 100644
--- a/tests/test_json.py
+++ b/tests/test_json.py
@@ -1,4 +1,5 @@
 import datetime
+import decimal
 import io
 import uuid
 
@@ -187,6 +188,11 @@ def test_jsonify_uuid_types(app, client):
     assert rv_uuid == test_uuid
 
 
+def test_json_decimal():
+    rv = flask.json.dumps(decimal.Decimal("0.003"))
+    assert rv == '"0.003"'
+
+
 def test_json_attr(app, client):
     @app.route("/add", methods=["POST"])
     def add():
diff --git a/tox.ini b/tox.ini
index c24ec0ff..50bf2660 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,8 @@
 [tox]
 envlist =
-    py{39,38,37,36,py3}
-    py39-click7
+    py3{11,10,9,8,7},pypy3{8,7}
+    py310-min
+    py37-dev
     style
     typing
     docs
@@ -10,8 +11,8 @@ skip_missing_interpreters = true
 [testenv]
 deps =
     -r requirements/tests.txt
-
-    click7: click<8
+    min: -r requirements/tests-pallets-min.txt
+    dev: -r requirements/tests-pallets-dev.txt
 
     examples/tutorial[test]
     examples/javascript[test]