Having a deprecated API just randomly return failures is an awful idea!

Better to give an actual timeline (future version & date) for when deprecated functionality / functions will be removed, and in the meantime, if the language supports it, mark those functions as deprecated (e.g. C++ [[deprecated]] attribute) so that developers see compilation warnings if they failed to read the release notes.

I don't think that was a serious suggestion, the article says it is sarcasm near the end.

But yes, that would be the worst idea ever.

Yep. I'll admit I've acted faster to hard set dates than some "in the future" message. I've also seen some tools become really noisy about deprecation spanning many lines AND repeating. Please don't log the same message over and over for each instance. Color or add emoji if you must to grab attention, but once is enough. It's annoying when you can't do anything about it at that time and have to sift through this extra noise when hunting down another issue in the CI log. Add a link that goes over it in more detail and how to migrate for that specific deprecation.