diff --git a/pkgs/development/python-modules/tinycss2/default.nix b/pkgs/development/python-modules/tinycss2/default.nix
index 35c8578cab44..5e6f441d3d3b 100644
--- a/pkgs/development/python-modules/tinycss2/default.nix
+++ b/pkgs/development/python-modules/tinycss2/default.nix
@@ -9,7 +9,7 @@
 
 buildPythonPackage rec {
   pname = "tinycss2";
-  version = "1.1.1";
+  version = "1.2.1";
   format = "pyproject";
 
   disabled = pythonOlder "3.6";
@@ -17,10 +17,10 @@ buildPythonPackage rec {
   src = fetchFromGitHub {
     owner = "kozea";
     repo = "tinycss2";
-    rev = "v${version}";
+    rev = "refs/tags/v${version}";
     # for tests
     fetchSubmodules = true;
-    hash = "sha256-RUF/3cjNgDFofoxl9iKY3u5ZAVVQmXu2Qbb5U4brdcQ=";
+    hash = "sha256-rJtxMmW30NK+E+Dhh/fu6FPrEojWWdoEWNt0raYEubs=";
   };
 
   postPatch = ''