diff --git a/pkgs/by-name/op/openscad-unstable/package.nix b/pkgs/by-name/op/openscad-unstable/package.nix
index b4e57ca17e3f..b584019221ff 100644
--- a/pkgs/by-name/op/openscad-unstable/package.nix
+++ b/pkgs/by-name/op/openscad-unstable/package.nix
@@ -121,7 +121,7 @@ clangStdenv.mkDerivation rec {
     "-DUSE_BUILTIN_OPENCSG=OFF"
     "-DUSE_BUILTIN_MANIFOLD=OFF"
     "-DUSE_BUILTIN_CLIPPER2=OFF"
-    "-DOPENSCAD_VERSION=\"${builtins.replaceStrings [ "-" ] [ "." ] version}\""
+    "-DOPENSCAD_VERSION=\"${builtins.replaceStrings [ "-" ] [ "." ] (lib.strings.getVersion version)}\""
     "-DCMAKE_UNITY_BUILD=OFF" # broken compile with unity
     # IPO
     "-DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld"