diff --git a/pkgs/development/python-modules/pyflunearyou/default.nix b/pkgs/development/python-modules/pyflunearyou/default.nix
index ea59fa0dc10f..cd04d00ee32e 100644
--- a/pkgs/development/python-modules/pyflunearyou/default.nix
+++ b/pkgs/development/python-modules/pyflunearyou/default.nix
@@ -9,6 +9,7 @@
 , pytest-aiohttp
 , pytestCheckHook
 , pythonOlder
+, pythonRelaxDepsHook
 , msgpack
 , ujson
 }:
@@ -27,13 +28,14 @@ buildPythonPackage rec {
     sha256 = "sha256-Q65OSE4qckpvaIvZULBR434i7hwuVM97eSq1Blb1oIU=";
   };
 
-  postPatch = ''
-    substituteInPlace pyproject.toml \
-      --replace 'ujson = ">=1.35,<5.0"' 'ujson = "*"'
-  '';
+  pythonRelaxDeps = [
+    "aiocache"
+    "ujson"
+  ];
 
   nativeBuildInputs = [
     poetry-core
+    pythonRelaxDepsHook
   ];
 
   propagatedBuildInputs = [