diff --git a/pkgs/by-name/de/devpi-client/package.nix b/pkgs/by-name/de/devpi-client/package.nix
index 109d2213eafe..f28848a11253 100644
--- a/pkgs/by-name/de/devpi-client/package.nix
+++ b/pkgs/by-name/de/devpi-client/package.nix
@@ -43,6 +43,7 @@ python3.pkgs.buildPythonApplication (finalAttrs: {
   ++ (with python3.pkgs; [
     mercurial
     mock
+    packaging-legacy
     pypitoken
     pytestCheckHook
     sphinx