I see that the best solution would be if InterSystems would make this package available as an open source, with an option to upgrade any existing instance with the open-source version by using IPM for instance

In this case, any team that keeps using ZEN may provide their thoughts on how the modern ZEN should look in the form of PullRequests. There would be a place to post bugs and feature requests, which some community members may help to solve for everyone.

ObjectScript does not support undescore sign in the names, and requires using double quotes to override this

$$$ThrowOnError(mymodule."validate_header"())

instead of using nc, which will not be able to send a full header, you could use my tool iscctl, which will connect, only if the server is available, and it will be logged in correctly. let me know if you would need some updates in the tool