Apple Developer Forum links broken after WWDC 2020 forum upgrade
I logged in to the new Apple Developer Forum.  Under my profile, I still have links to my old topics. They do still exist in the new Forum.
The URLs have changed. They now use /thread/ rather than /message/ and the thread/message ID has changed:
OLD: https://developer.apple.com/forums/message/335101  
NEW: https://developer.apple.com/forums/thread/109652

and the same question posted to Ask Different: Why can I not set Safari keyboard shortcuts?
That's the details of the change. I don't know if there's a way to link the old and new IDs.