The option `services.stirling-pdf' does not exist

A service for stirling-pdf seemingly should exist according to this resource:

Yet when enabling as a system (not home-manager) module, I’m getting a “does not exist” error:

{ 
  config, 
  pkgs, 
  ... 
}:

let
  app = "stirling-pdf";
in

{
  services.${app} = {
    enable = true;
    environment = {
      SERVER_PORT = 2000;
    };
  };

I havn’t run into this before with any other service…can anyone help me understand what is going on? Is this an actual bug or am I missing something here?

It’s available on the unstable channel, but not on 24.05. You can either wait for NixOS 24.11 or import the module from the unstable channel.