diff --git a/pkgs/development/python-modules/gbulb/default.nix b/pkgs/development/python-modules/gbulb/default.nix
index c6306da0ee63..f2a772d1ad66 100644
--- a/pkgs/development/python-modules/gbulb/default.nix
+++ b/pkgs/development/python-modules/gbulb/default.nix
@@ -10,13 +10,13 @@
 
 buildPythonPackage rec {
   pname = "gbulb";
-  version = "0.6.3";
+  version = "0.6.4";
 
   src = fetchFromGitHub {
     owner = "beeware";
     repo = "gbulb";
-    rev = "v${version}";
-    sha256 = "sha256-QNpZf1zfe6r6MtmYMWSrXPsXm5iX36oMx4GnXiTYPaQ=";
+    rev = "refs/tags/v${version}";
+    sha256 = "sha256-AdZSvxix0cpoFQSrslGl+hB/s6Nh0EsWMQmXZAJVJOg=";
   };
 
   propagatedBuildInputs = [