diff --git a/pkgs/development/coq-modules/stalmarck/default.nix b/pkgs/development/coq-modules/stalmarck/default.nix
index e493321d8a0a..94df3e3c0a7a 100644
--- a/pkgs/development/coq-modules/stalmarck/default.nix
+++ b/pkgs/development/coq-modules/stalmarck/default.nix
@@ -17,7 +17,7 @@ let
       (case (isEq "8.20") "8.20.0")
     ] null;
   release = {
-    "8.20.0".sha256 = "sha256-jITxQT1jLyZvWCGPnmK8i3IrwsZwMPOV0aBe9r22TIQ=";
+    "8.20.0".hash = "sha256-jITxQT1jLyZvWCGPnmK8i3IrwsZwMPOV0aBe9r22TIQ=";
   };
   releaseRev = v: "v${v}";