_: pkgs:
let
  unstable = import <unstable> { overlays = [ ]; };
  overrideUntilVersion = p: v: (if pkgs ? ${p} && pkgs.lib.versionAtLeast pkgs.${p}.version v then pkgs else unstable).${p};
in
builtins.mapAttrs overrideUntilVersion {
  aws-sam-cli = "1.52.0";
  darktable = "4.0.0";
  efficient-compression-tool = "0.9.1";
  kitty = "0.25.2";
}