diff --git a/pkgs/development/python-modules/twentemilieu/default.nix b/pkgs/development/python-modules/twentemilieu/default.nix
index fb5617321747..f326a56d8d67 100644
--- a/pkgs/development/python-modules/twentemilieu/default.nix
+++ b/pkgs/development/python-modules/twentemilieu/default.nix
@@ -2,6 +2,7 @@
 , buildPythonPackage
 , pythonOlder
 , fetchFromGitHub
+, poetry-core
 , aiohttp
 , yarl
 , aresponses
@@ -11,16 +12,27 @@
 
 buildPythonPackage rec {
   pname = "twentemilieu";
-  version = "0.3.0";
-  disabled = pythonOlder "3.7";
+  version = "0.5.0";
+  format = "pyproject";
+
+  disabled = pythonOlder "3.8";
 
   src = fetchFromGitHub {
     owner = "frenck";
     repo = "python-twentemilieu";
     rev = "v${version}";
-    sha256 = "1ff35sh73m2s7fh4d8p2pjwdbfljswr8b8lpcjybz8nsh0286xph";
+    sha256 = "sha256-7HQ0+h8oiyY+TacQdX84K0r994rH0AMZAvZz8PUvQl0=";
   };
 
+  postPatch = ''
+    substituteInPlace pyproject.toml \
+      --replace "--cov" ""
+  '';
+
+  nativeBuildInputs = [
+    poetry-core
+  ];
+
   propagatedBuildInputs = [
     aiohttp
     yarl