diff --git a/pkgs/development/python-modules/rsa/default.nix b/pkgs/development/python-modules/rsa/default.nix
index c1dec194932c..a8392a452856 100644
--- a/pkgs/development/python-modules/rsa/default.nix
+++ b/pkgs/development/python-modules/rsa/default.nix
@@ -5,7 +5,6 @@
   poetry-core,
   pyasn1,
   pytestCheckHook,
-  pythonOlder,
 }:
 
 buildPythonPackage rec {
@@ -20,10 +19,6 @@ buildPythonPackage rec {
     hash = "sha256-PwaRe+ICy0UoguXSMSh3PFl5R+YAhJwNdNN9isadlJY=";
   };
 
-  preConfigure = lib.optionalString (pythonOlder "3.7") ''
-    substituteInPlace setup.py --replace "open('README.md')" "open('README.md',encoding='utf-8')"
-  '';
-
   nativeBuildInputs = [ poetry-core ];
 
   propagatedBuildInputs = [ pyasn1 ];