Outdated Producer warning is issued in the following situation:
Producer '<producer>' uses outdated references. Please republish '<producer>' to prevent runtime errors
Your current module (e.g.: Mymodule) has one or more references to another module (e.g.: module1) which is referencing other producers that have changed since it (module1) was last published.
Re-Publish module1 to refresh its references, and retry Mymodule publication, afterwards.