Look at the backlog of issues in their GitHub for backports. You'll see detailed lists of reported and fixed breakages. The lists aren't small... Now go on to imagine the ones people don't report and instead patch and fix them locally. We aren't even talking about Julia code fixes, often these involve the C that creates it and are a nightmare to diagnose. I can't reply to your post unfortunately the thread is too long.

How exactly are Julia releases broken?