diff --git a/pkgs/development/python-modules/pymc/default.nix b/pkgs/development/python-modules/pymc/default.nix
index 4fce3800ef1..51a669b9c0a 100644
--- a/pkgs/development/python-modules/pymc/default.nix
+++ b/pkgs/development/python-modules/pymc/default.nix
@@ -16,7 +16,7 @@
 
 buildPythonPackage rec {
   pname = "pymc";
-  version = "4.0.0";
+  version = "4.0.1";
   format = "setuptools";
 
   disabled = pythonOlder "3.7";
@@ -24,8 +24,8 @@ buildPythonPackage rec {
   src = fetchFromGitHub {
     owner = "pymc-devs";
     repo = "pymc";
-    rev = "v${version}";
-    hash = "sha256-ZMuDQJ+bmrQlrem/OqU/hIie3ZQkAqayU3N8ZtaW7xo=";
+    rev = "refs/tags/v${version}";
+    hash = "sha256-muNwq9ZSxbcFNoitP1k8LEjOxJWft9jqci5q2IGu7F8=";
   };
 
   nativeBuildInputs = [