Niko Trimmel on Nostr: the changes in 4.2 (if those are the ones you mean) were communicated via a blog post ...

the changes in 4.2 (if those are the ones you mean) were communicated via a blog post that was shared https://blog.joinmastodon.org/2023/09/mastodon-4.2/ and definitely in some mastodon posts by users as well back then