That being said, I do intend to publish updates when new versions of either Rerun or Bevy land; if only to experiment with new APIs as they come online.
Now, to answer your question, I've been using Bevy since the 0.1 release and, in my experience, keeping up with the changes upstream has always been pretty painless. Their organization nand release process is top-notch, with some of the most high quality changelogs and migration guides I've ever seen in any project, and releases are rare enough (~about once a quarter) to just not be an issue.
The community maintains compatibility matrices such as this one [2], and things generally just work :tm:.
[1] https://www.reddit.com/r/rust/comments/1b6bqv1/revy_proofofc...
[2] https://github.com/rerun-io/revy?tab=readme-ov-file#compatib...