diff --git a/.appveyor.yml b/.appveyor.yml
deleted file mode 100644
index e7e9c80f9..000000000
--- a/.appveyor.yml
+++ /dev/null
@@ -1,24 +0,0 @@
-environment:
-  matrix:
-
-    # For Python versions available on Appveyor, see
-    # https://www.appveyor.com/docs/windows-images-software/#python
-    # Only Python 3.6+ is supported
-
-    - PYTHON: "C:\\Python36"
-    - PYTHON: "C:\\Python37"
-    - PYTHON: "C:\\Python36-x64"
-    - PYTHON: "C:\\Python37-x64"
-
-install:
-  # Prepend Python installation and scripts (e.g. pytest) to PATH
-  - set PATH=%PYTHON%;%PYTHON%\\Scripts;%PATH%
-
-  # Install tox
-  - "pip install tox"
-
-build: off
-
-test_script:
-  # run tests
-  - "tox -e appveyor"
diff --git a/README.rst b/README.rst
index 07971b586..b688b8483 100644
--- a/README.rst
+++ b/README.rst
@@ -3,7 +3,7 @@ python-can
 
 |release| |python_implementation| |downloads| |downloads_monthly| |formatter|
 
-|docs| |build_travis| |build_appveyor| |coverage| |mergify|
+|docs| |build_travis| |coverage| |mergify|
 
 .. |release| image:: https://img.shields.io/pypi/v/python-can.svg
    :target: https://pypi.python.org/pypi/python-can/
@@ -33,10 +33,6 @@ python-can
    :target: https://travis-ci.com/hardbyte/python-can
    :alt: Travis CI Server for develop branch
 
-.. |build_appveyor| image:: https://img.shields.io/appveyor/ci/hardbyte/python-can/develop.svg?label=AppVeyor
-   :target: https://ci.appveyor.com/project/hardbyte/python-can/history
-   :alt: AppVeyor CI Server for develop branch
-
 .. |coverage| image:: https://codecov.io/gh/hardbyte/python-can/branch/develop/graph/badge.svg
    :target: https://codecov.io/gh/hardbyte/python-can/branch/develop
    :alt: Test coverage reports on Codecov.io
diff --git a/test/config.py b/test/config.py
index f04bf3206..58ad780fc 100644
--- a/test/config.py
+++ b/test/config.py
@@ -5,7 +5,7 @@
 This module contains various configuration for the tests.
 
 Some tests are skipped when run on a CI server because they are not
-reproducible, see #243 (https://github.com/hardbyte/python-can/issues/243).
+reproducible, see for example #243 and #940.
 """
 
 import platform
@@ -20,23 +20,17 @@ def env(name: str) -> bool:
 
 # see here for the environment variables that are set on the CI servers:
 #   - https://docs.travis-ci.com/user/environment-variables/
-#   - https://www.appveyor.com/docs/environment-variables/
+#   - https://docs.github.com/en/actions/reference/environment-variables#default-environment-variables
 
 IS_TRAVIS = env("TRAVIS")
-IS_APPVEYOR = env("APPVEYOR")
 IS_GITHUB_ACTIONS = env("GITHUB_ACTIONS")
 
-IS_CI = (
-    IS_TRAVIS
-    or IS_APPVEYOR
-    or IS_GITHUB_ACTIONS
-    or env("CI")
-    or env("CONTINUOUS_INTEGRATION")
-)
+IS_CI = IS_TRAVIS or IS_GITHUB_ACTIONS or env("CI") or env("CONTINUOUS_INTEGRATION")
 
-if IS_APPVEYOR and IS_TRAVIS and IS_GITHUB_ACTIONS:
+if IS_TRAVIS and IS_GITHUB_ACTIONS:
     raise EnvironmentError(
-        "only one of IS_APPVEYOR and IS_TRAVIS and GITHUB_ACTIONS may be True at the same time"
+        f"only one of IS_TRAVIS ({IS_TRAVIS}) and IS_GITHUB_ACTIONS ({IS_GITHUB_ACTIONS}) may be True at the "
+        "same time"
     )
 
 
@@ -47,19 +41,20 @@ def env(name: str) -> bool:
 IS_LINUX = "linux" in _sys
 IS_OSX = "darwin" in _sys
 IS_UNIX = IS_LINUX or IS_OSX
+del _sys
 
 if (IS_WINDOWS and IS_LINUX) or (IS_LINUX and IS_OSX) or (IS_WINDOWS and IS_OSX):
     raise EnvironmentError(
-        "only one of IS_WINDOWS ({}), IS_LINUX ({}) and IS_OSX ({}) ".format(
-            IS_WINDOWS, IS_LINUX, IS_OSX
-        )
-        + "can be True at the same time "
-        + '(platform.system() == "{}")'.format(platform.system())
+        f"only one of IS_WINDOWS ({IS_WINDOWS}), IS_LINUX ({IS_LINUX}) and IS_OSX ({IS_OSX}) "
+        f'can be True at the same time (platform.system() == "{platform.system()}")'
     )
 
+
 # ############################## Implementations
+
 IS_PYPY = platform.python_implementation() == "PyPy"
 
+
 # ############################## What tests to run
 
 TEST_CAN_FD = True
diff --git a/test/test_message_sync.py b/test/test_message_sync.py
index a20cc9d65..6e6a89a4d 100644
--- a/test/test_message_sync.py
+++ b/test/test_message_sync.py
@@ -14,7 +14,7 @@
 
 from can import MessageSync, Message
 
-from .config import IS_CI, IS_APPVEYOR, IS_TRAVIS, IS_OSX, IS_GITHUB_ACTIONS, IS_LINUX
+from .config import IS_CI, IS_TRAVIS, IS_OSX, IS_GITHUB_ACTIONS, IS_LINUX
 from .message_helper import ComparingMessagesTestCase
 from .data.example_data import TEST_MESSAGES_BASE
 
@@ -31,7 +31,7 @@ def inc(value):
 
 
 skip_on_unreliable_platforms = unittest.skipIf(
-    IS_APPVEYOR or (IS_TRAVIS and IS_OSX) or (IS_GITHUB_ACTIONS and not IS_LINUX),
+    (IS_TRAVIS and IS_OSX) or (IS_GITHUB_ACTIONS and not IS_LINUX),
     "this environment's timings are too unpredictable",
 )
 
diff --git a/tox.ini b/tox.ini
index 46bb17456..a29c3cafe 100644
--- a/tox.ini
+++ b/tox.ini
@@ -31,17 +31,6 @@ passenv =
     TRAVIS_*
     TEST_SOCKETCAN
 
-commands_post =
-    codecov -X gcov
-
-[testenv:appveyor]
-passenv =
-    CI
-    APPVEYOR
-    APPVEYOR_*
-
-extras = neovi
-
 commands_post =
     codecov -X gcov