It's really hard to say, it depends on what has changed in the game code. During active development, all kinds of tinkering can go on (improvements, cleaning up messy code, moving functionality around, renaming methods or variables, ...), even if the code isn't part of the new content. I don't think predictions are possible, but your chances are better the more active a mod author is. After the next Valheim update, they'll need time to figure out the changes and update their own code.