No backup prompt when opening old worlds

As in the title, the "create backup" message when opening old (in my case 1.16.5.) world in the newest version is gone, world just loads. That backup prompt existed in in stable versions before, added screenshot from version 1.16.5. as a proof.

Steps to recreate:
1. Create a world in older version
2. Try opening the world in 1.17.
3. World load without usual backup prompt

EDIT: deleted the part about "!" mark, it was never supposed to be on updating from stable version to never stable version, added a screenshot as a proof of backup prompt existence, and reworded the bug report to make it clearer what is the issue