diff --git a/pkgs/development/tools/devpi-client/default.nix b/pkgs/development/tools/devpi-client/default.nix
index 86333625725..b308d8a48c3 100644
--- a/pkgs/development/tools/devpi-client/default.nix
+++ b/pkgs/development/tools/devpi-client/default.nix
@@ -13,7 +13,6 @@
 , pluggy
 , py
 , pytestCheckHook
-, pytest-flake8
 , setuptools
 , sphinx
 , tox
@@ -30,6 +29,11 @@ buildPythonApplication rec {
     hash = "sha256-Ni6ybpUTankkkYYcwnKNFKYwmp1MTxOnucPm/TneWOw=";
   };
 
+  postPatch = ''
+    substituteInPlace tox.ini \
+      --replace "--flake8" ""
+  '';
+
   buildInputs = [
     glibcLocales
   ];
@@ -50,7 +54,6 @@ buildPythonApplication rec {
     mercurial
     mock
     pytestCheckHook
-    pytest-flake8
     sphinx
     tox
     webtest