diff --git a/pkgs/development/tools/comby/default.nix b/pkgs/development/tools/comby/default.nix
index f6f7357c1557..ad7ab8559688 100644
--- a/pkgs/development/tools/comby/default.nix
+++ b/pkgs/development/tools/comby/default.nix
@@ -16,7 +16,7 @@ let
       inherit pname preBuild;
       version = "1.8.1";
       duneVersion = "3";
-      minimalOcamlVersion = "4.08.1";
+      minimalOCamlVersion = "4.08.1";
       doCheck = true;
 
       src = fetchFromGitHub {