diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index da150ae19ca..92ea89a043a 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -18898,7 +18898,7 @@ with pkgs;
 
   unigine-valley = callPackage ../applications/graphics/unigine-valley { };
 
-  inherit (ocamlPackages) unison;
+  inherit (ocaml-ng.ocamlPackages_4_05) unison;
 
   unpaper = callPackage ../tools/graphics/unpaper { };