diff --git a/pkgs/applications/misc/ulauncher/default.nix b/pkgs/applications/misc/ulauncher/default.nix
index 81e273dd39d..f1439dc7d16 100644
--- a/pkgs/applications/misc/ulauncher/default.nix
+++ b/pkgs/applications/misc/ulauncher/default.nix
@@ -66,7 +66,6 @@ python3Packages.buildPythonApplication rec {
     mock
     pytest
     pytest-mock
-    pytestpep8
     xvfb_run
   ];
 
@@ -95,7 +94,7 @@ python3Packages.buildPythonApplication rec {
     # skip tests in invocation that handle paths that
     # aren't nix friendly (i think)
     xvfb-run -s '-screen 0 1024x768x16' \
-      pytest -k 'not TestPath and not test_handle_key_press_event' --pep8 tests
+      pytest -k 'not TestPath and not test_handle_key_press_event' tests
 
     runHook postCheck
   '';
diff --git a/pkgs/development/python-modules/dyn/default.nix b/pkgs/development/python-modules/dyn/default.nix
index 6e03a33f29b..cc7a330e97c 100644
--- a/pkgs/development/python-modules/dyn/default.nix
+++ b/pkgs/development/python-modules/dyn/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, fetchPypi, pytest, pytestcov, mock, pytestpep8
+{ stdenv, buildPythonPackage, fetchPypi, pytest, pytestcov, mock
 , pytest_xdist, covCore, glibcLocales }:
 
 buildPythonPackage rec {
@@ -16,7 +16,6 @@ buildPythonPackage rec {
     pytest
     pytestcov
     mock
-    pytestpep8
     pytest_xdist
     covCore
   ];
diff --git a/pkgs/development/python-modules/ics/default.nix b/pkgs/development/python-modules/ics/default.nix
index 08799a9fb4b..30661c9bc91 100644
--- a/pkgs/development/python-modules/ics/default.nix
+++ b/pkgs/development/python-modules/ics/default.nix
@@ -1,6 +1,6 @@
 { stdenv, buildPythonPackage, fetchFromGitHub, pythonOlder
 , tatsu, arrow
-, pytestCheckHook, pytestpep8, pytest-flakes
+, pytestCheckHook, pytest-flakes
 }:
 
 buildPythonPackage rec {
@@ -20,9 +20,10 @@ buildPythonPackage rec {
   postPatch = ''
     substituteInPlace requirements.txt \
       --replace "arrow>=0.11,<0.15" "arrow"
+    substituteInPlace setup.cfg --replace "--pep8" ""
   '';
 
-  checkInputs = [ pytestCheckHook pytestpep8 pytest-flakes ];
+  checkInputs = [ pytestCheckHook pytest-flakes ];
 
   meta = with stdenv.lib; {
     description = "Pythonic and easy iCalendar library (RFC 5545)";
diff --git a/pkgs/development/python-modules/jsonlines/default.nix b/pkgs/development/python-modules/jsonlines/default.nix
index cde440380b4..82ddb3bf23a 100644
--- a/pkgs/development/python-modules/jsonlines/default.nix
+++ b/pkgs/development/python-modules/jsonlines/default.nix
@@ -1,5 +1,5 @@
 { lib, fetchFromGitHub, buildPythonPackage, six
-, flake8, pep8-naming, pytest, pytestcov, pytestpep8 }:
+, flake8, pep8-naming, pytest, pytestcov }:
 
 buildPythonPackage rec {
   pname = "jsonlines";
@@ -14,7 +14,7 @@ buildPythonPackage rec {
 
   propagatedBuildInputs = [ six ];
 
-  checkInputs = [ flake8 pep8-naming pytest pytestcov pytestpep8 ];
+  checkInputs = [ flake8 pep8-naming pytest pytestcov ];
   checkPhase = ''
     pytest
   '';
diff --git a/pkgs/development/python-modules/keras/default.nix b/pkgs/development/python-modules/keras/default.nix
index 8b6301ab59b..f2243a1531f 100644
--- a/pkgs/development/python-modules/keras/default.nix
+++ b/pkgs/development/python-modules/keras/default.nix
@@ -1,5 +1,5 @@
 { stdenv, buildPythonPackage, fetchPypi
-, pytest, pytestcov, pytestpep8, pytest_xdist
+, pytest, pytestcov, pytest_xdist
 , six, numpy, scipy, pyyaml, h5py
 , keras-applications, keras-preprocessing
 }:
@@ -16,7 +16,6 @@ buildPythonPackage rec {
   checkInputs = [
     pytest
     pytestcov
-    pytestpep8
     pytest_xdist
   ];
 
diff --git a/pkgs/development/python-modules/mwclient/default.nix b/pkgs/development/python-modules/mwclient/default.nix
index 2744ff9a277..644f01fdb1f 100644
--- a/pkgs/development/python-modules/mwclient/default.nix
+++ b/pkgs/development/python-modules/mwclient/default.nix
@@ -1,6 +1,6 @@
 { stdenv, buildPythonPackage, fetchFromGitHub
 , requests, requests_oauthlib, six
-, pytest, pytestpep8, pytestcache, pytestcov, responses, mock
+, pytest, pytestcache, pytestcov, responses, mock
 }:
 
 buildPythonPackage rec {
@@ -14,7 +14,7 @@ buildPythonPackage rec {
     sha256 = "120snnsh9n5svfwkyj1w9jrxf99jnqm0jk282yypd3lpyca1l9hj";
   };
 
-  checkInputs = [ pytest pytestpep8 pytestcache pytestcov responses mock ];
+  checkInputs = [ pytest pytestcache pytestcov responses mock ];
 
   propagatedBuildInputs = [ requests requests_oauthlib six ];
 
diff --git a/pkgs/development/python-modules/progressbar2/default.nix b/pkgs/development/python-modules/progressbar2/default.nix
index 23ebc935459..789828b7143 100644
--- a/pkgs/development/python-modules/progressbar2/default.nix
+++ b/pkgs/development/python-modules/progressbar2/default.nix
@@ -6,7 +6,6 @@
 , python-utils
 , sphinx
 , flake8
-, pytestpep8
 , pytest-flakes
 , pytestcov
 , pytestcache
@@ -26,7 +25,7 @@ buildPythonPackage rec {
   propagatedBuildInputs = [ python-utils ];
   nativeBuildInputs = [ pytestrunner ];
   checkInputs = [
-    pytest sphinx flake8 pytestpep8 pytest-flakes pytestcov
+    pytest sphinx flake8 pytest-flakes pytestcov
     pytestcache freezegun
   ];
   # ignore tests on the nix wrapped setup.py
diff --git a/pkgs/development/python-modules/pydocstyle/2.nix b/pkgs/development/python-modules/pydocstyle/2.nix
index 21e39b68d12..9ce4ffc0f81 100644
--- a/pkgs/development/python-modules/pydocstyle/2.nix
+++ b/pkgs/development/python-modules/pydocstyle/2.nix
@@ -1,6 +1,6 @@
 { lib, buildPythonPackage, fetchFromGitHub, isPy3k, pythonOlder
 , snowballstemmer, six, configparser
-, pytest, pytestpep8, mock, pathlib }:
+, pytest, mock, pathlib }:
 
 buildPythonPackage rec {
   pname = "pydocstyle";
@@ -17,11 +17,11 @@ buildPythonPackage rec {
 
   propagatedBuildInputs = [ snowballstemmer six ] ++ lib.optional (!isPy3k) configparser;
 
-  checkInputs = [ pytest pytestpep8 mock ] ++ lib.optional (pythonOlder "3.4") pathlib;
+  checkInputs = [ pytest mock ] ++ lib.optional (pythonOlder "3.4") pathlib;
 
   checkPhase = ''
     # test_integration.py installs packages via pip
-    py.test --pep8 --cache-clear -vv src/tests -k "not test_integration"
+    py.test --cache-clear -vv src/tests -k "not test_integration"
   '';
 
   meta = with lib; {
diff --git a/pkgs/development/python-modules/pydocstyle/default.nix b/pkgs/development/python-modules/pydocstyle/default.nix
index cef9e964425..36c61ace856 100644
--- a/pkgs/development/python-modules/pydocstyle/default.nix
+++ b/pkgs/development/python-modules/pydocstyle/default.nix
@@ -1,7 +1,6 @@
 { lib, buildPythonPackage, fetchFromGitHub, isPy3k
 , mock
 , pytest
-, pytestpep8
 , snowballstemmer
 }:
 
diff --git a/pkgs/development/python-modules/pylti/default.nix b/pkgs/development/python-modules/pylti/default.nix
index 752755700b2..a6778a4aa7e 100644
--- a/pkgs/development/python-modules/pylti/default.nix
+++ b/pkgs/development/python-modules/pylti/default.nix
@@ -14,7 +14,6 @@
 , pytestcov
 , covCore
 , pytest-flakes
-, pytestpep8
 , sphinx
 , mock
 , chalice
@@ -35,7 +34,7 @@ buildPythonPackage rec {
   propagatedBuildInputs = [ httplib2 oauth oauth2 semantic-version ];
   checkInputs = [
     flask httpretty oauthlib pyflakes pytest pytestcache pytestcov covCore
-    pytest-flakes pytestpep8 sphinx mock chalice
+    pytest-flakes sphinx mock chalice
   ];
 
   src = fetchPypi {
diff --git a/pkgs/development/python-modules/pytest-factoryboy/default.nix b/pkgs/development/python-modules/pytest-factoryboy/default.nix
index 44a59730146..48c5020a44f 100644
--- a/pkgs/development/python-modules/pytest-factoryboy/default.nix
+++ b/pkgs/development/python-modules/pytest-factoryboy/default.nix
@@ -7,7 +7,6 @@
 , factory_boy
 , pytestcache
 , pytestcov
-, pytestpep8
 , mock
 }:
 
@@ -22,6 +21,9 @@ buildPythonPackage rec {
     sha256 = "0m1snyybq2k51khlydhisq300vzys897vdbsicph628iran950hn";
   };
 
+  # TODO: remove in next release, it's removed in master.
+  postPatch = "substituteInPlace tox.ini --replace '--pep8' ''";
+
   propagatedBuildInputs = [ factory_boy inflection pytest ];
 
   # The project uses tox, which we can't. So we simply run pytest manually.
@@ -30,7 +32,6 @@ buildPythonPackage rec {
     pytestCheckHook
     pytestcache
     pytestcov
-    pytestpep8
   ];
   pytestFlagsArray = [ "--ignore=docs" ];
 
diff --git a/pkgs/development/python-modules/pytest-flakes/default.nix b/pkgs/development/python-modules/pytest-flakes/default.nix
index 38156cc0ccf..440cc632185 100644
--- a/pkgs/development/python-modules/pytest-flakes/default.nix
+++ b/pkgs/development/python-modules/pytest-flakes/default.nix
@@ -1,5 +1,4 @@
 { stdenv, buildPythonPackage, fetchPypi, pythonOlder
-, pytestpep8
 , pytest
 , pyflakes
 }:
@@ -16,7 +15,7 @@ buildPythonPackage rec {
     sha256 = "bf070c5485dad82d5b5f5d0eb08d269737e378492d9a68f5223b0a90924c7754";
   };
 
-  checkInputs = [ pytestpep8 pytest ];
+  checkInputs = [ pytest ];
   propagatedBuildInputs = [ pytest pyflakes ];
 
   # no longer passes
diff --git a/pkgs/development/python-modules/pytest-pep8/default.nix b/pkgs/development/python-modules/pytest-pep8/default.nix
deleted file mode 100644
index 82a900a9d2f..00000000000
--- a/pkgs/development/python-modules/pytest-pep8/default.nix
+++ /dev/null
@@ -1,28 +0,0 @@
-{ stdenv, buildPythonPackage, fetchPypi
-, pytest, pytestcache, pep8 }:
-
-buildPythonPackage rec {
-  pname = "pytest-pep8";
-  version = "1.0.6";
-
-  src = fetchPypi {
-    inherit pname version;
-    sha256 = "06032agzhw1i9d9qlhfblnl3dw5hcyxhagn7b120zhrszbjzfbh3";
-  };
-
-  buildInputs = [ pytest ];
-  propagatedBuildInputs = [ pytestcache pep8 ];
-
-  checkPhase = ''
-    py.test
-  '';
-
-  # Fails
-  doCheck = false;
-
-  meta = with stdenv.lib; {
-    license = licenses.mit;
-    homepage = "https://pypi.python.org/pypi/pytest-pep8";
-    description = "pytest plugin to check PEP8 requirements";
-  };
-}
diff --git a/pkgs/development/python-modules/pytest-quickcheck/default.nix b/pkgs/development/python-modules/pytest-quickcheck/default.nix
index 8db28159d9d..7db982ed857 100644
--- a/pkgs/development/python-modules/pytest-quickcheck/default.nix
+++ b/pkgs/development/python-modules/pytest-quickcheck/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, buildPythonPackage, fetchPypi, pytest, pytest-flakes, pytestpep8, tox }:
+{ stdenv, buildPythonPackage, fetchPypi, pytest, pytest-flakes, tox }:
 buildPythonPackage rec {
   pname = "pytest-quickcheck";
   version = "0.8.6";
@@ -9,7 +9,7 @@ buildPythonPackage rec {
   };
 
   buildInputs = [ pytest ];
-  propagatedBuildInputs = [ pytest-flakes pytestpep8 tox ];
+  propagatedBuildInputs = [ pytest-flakes tox ];
 
   meta = with stdenv.lib; {
     license = licenses.asl20;
diff --git a/pkgs/development/python-modules/python-utils/default.nix b/pkgs/development/python-modules/python-utils/default.nix
index 936a1eb2e3e..60160d270b7 100644
--- a/pkgs/development/python-modules/python-utils/default.nix
+++ b/pkgs/development/python-modules/python-utils/default.nix
@@ -1,4 +1,4 @@
-{ lib, buildPythonPackage, fetchPypi, pytest, pytestrunner, pytestcov, pytest-flakes, pytestpep8, sphinx, six }:
+{ lib, buildPythonPackage, fetchPypi, pytestCheckHook, pytestrunner, pytestcov, pytest-flakes, sphinx, six }:
 
 buildPythonPackage rec {
   pname = "python-utils";
@@ -12,13 +12,10 @@ buildPythonPackage rec {
   postPatch = ''
     rm -r tests/__pycache__
     rm tests/*.pyc
+    substituteInPlace pytest.ini --replace "--pep8" ""
   '';
 
-  checkInputs = [ pytest pytestrunner pytestcov pytest-flakes pytestpep8 sphinx ];
-
-  checkPhase = ''
-    py.test tests
-  '';
+  checkInputs = [ pytestCheckHook pytestrunner pytestcov pytest-flakes sphinx ];
 
   propagatedBuildInputs = [ six ];
 
diff --git a/pkgs/development/python-modules/requests-unixsocket/default.nix b/pkgs/development/python-modules/requests-unixsocket/default.nix
index 5229dd96b75..f98b68c13a0 100644
--- a/pkgs/development/python-modules/requests-unixsocket/default.nix
+++ b/pkgs/development/python-modules/requests-unixsocket/default.nix
@@ -1,6 +1,6 @@
 { lib, buildPythonPackage, fetchPypi
 , pbr, requests
-, pytest, pytestpep8, waitress }:
+, pytest, waitress }:
 
 buildPythonPackage rec {
   pname = "requests-unixsocket";
@@ -14,7 +14,7 @@ buildPythonPackage rec {
   nativeBuildInputs = [ pbr ];
   propagatedBuildInputs = [ requests ];
 
-  checkInputs = [ pytest pytestpep8 waitress ];
+  checkInputs = [ pytest waitress ];
   checkPhase = ''
     rm pytest.ini
     py.test
diff --git a/pkgs/development/python-modules/subliminal/default.nix b/pkgs/development/python-modules/subliminal/default.nix
index 25e20a44118..77ddb125a94 100644
--- a/pkgs/development/python-modules/subliminal/default.nix
+++ b/pkgs/development/python-modules/subliminal/default.nix
@@ -20,7 +20,6 @@
 , sympy
 , vcrpy
 , pytest
-, pytestpep8
 , pytest-flakes
 , pytestcov
 , pytestrunner
@@ -42,7 +41,7 @@ buildPythonPackage rec {
   ] ++ lib.optional (!isPy3k) futures;
 
   checkInputs = [
-    sympy vcrpy pytest pytestpep8 pytest-flakes
+    sympy vcrpy pytest pytest-flakes
     pytestcov pytestrunner
   ];
 
diff --git a/pkgs/development/tools/devpi-server/default.nix b/pkgs/development/tools/devpi-server/default.nix
index 53950d08f76..7ddff92402c 100644
--- a/pkgs/development/tools/devpi-server/default.nix
+++ b/pkgs/development/tools/devpi-server/default.nix
@@ -30,24 +30,30 @@ python3Packages.buildPythonApplication rec {
   checkInputs = with python3Packages; [
     beautifulsoup4
     nginx
-    pytest
+    pytestCheckHook
     pytest-flake8
-    pytestpep8
     webtest
   ] ++ stdenv.lib.optionals isPy27 [ mock ];
 
   # root_passwd_hash tries to write to store
   # TestMirrorIndexThings tries to write to /var through ngnix
   # nginx tests try to write to /var
-  checkPhase = ''
-    PATH=$PATH:$out/bin HOME=$TMPDIR pytest \
-      ./test_devpi_server --slow -rfsxX \
-      --ignore=test_devpi_server/test_nginx_replica.py \
-      --ignore=test_devpi_server/test_streaming_nginx.py \
-      --ignore=test_devpi_server/test_streaming_replica_nginx.py \
-      -k 'not root_passwd_hash_option \
-          and not TestMirrorIndexThings'
+  preCheck = ''
+    export PATH=$PATH:$out/bin
+    export HOME=$TMPDIR
   '';
+  pytestFlagsArray = [
+    "./test_devpi_server"
+    "--slow"
+    "-rfsxX"
+    "--ignore=test_devpi_server/test_nginx_replica.py"
+    "--ignore=test_devpi_server/test_streaming_nginx.py"
+    "--ignore=test_devpi_server/test_streaming_replica_nginx.py"
+  ];
+  disabledTests = [
+    "root_passwd_hash_option"
+    "TestMirrorIndexThings"
+  ];
 
   meta = with stdenv.lib;{
     homepage = "http://doc.devpi.net";
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 421aca7033a..eeed74d4cad 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -5820,7 +5820,7 @@ in {
 
   pytest-pep257 = callPackage ../development/python-modules/pytest-pep257 { };
 
-  pytestpep8 = callPackage ../development/python-modules/pytest-pep8 { };
+  pytestpep8 = throw "pytestpep8 was removed because it is abandoned and no longer compatible with pytest v6.0"; # added 2020-12-10
 
   pytest-pylint = callPackage ../development/python-modules/pytest-pylint { };