Start with the upgrade guide and the changelog, not a social post. Note anything marked as a breaking change, a deprecation, or a security release.

Skim your composer.lock for the packages that moved. Most weeks the answer is “nothing you call has changed”. When something has, it is usually a signature, a default, or a config key.

Run the test suite on a branch before you merge. A quiet week is still worth ten minutes, because the weeks that are not quiet look the same at the start.