diff --git a/pkgs/development/python-modules/pymitsubishi/default.nix b/pkgs/development/python-modules/pymitsubishi/default.nix
index 4e42f014492b..181e2a716eeb 100644
--- a/pkgs/development/python-modules/pymitsubishi/default.nix
+++ b/pkgs/development/python-modules/pymitsubishi/default.nix
@@ -21,6 +21,11 @@ buildPythonPackage rec {
     hash = "sha256-frqyAXAP2O8TZzXx5ephcLSLJA9p0P74KJrPoSKPYYo=";
   };
 
+  postPatch = ''
+    # make sure pyproject.toml specifies the correct version
+    grep -qF 'version = "${version}"' pyproject.toml
+  '';
+
   build-system = [ setuptools ];
 
   dependencies = [