It's a fine line to walk. Don't change enough and you hemorrhage developers due to not supporting new and interesting features and concepts, change too much and you you hemorrhage developers who don't want to start a new project to run into the same problems as the last one, where an upgrade caused headaches. FWIW I think Rust's tagging of breaking changes (and eventually making them easy to identify and fix) as stated in a same level comment is wise no matter the strategy.
