The upcoming RB will contain a few breaks: Plugins that teleport players within the PlayerMove event will need to switch to just using event.setTo() as this now handles teleporting. This means that event.setTo() can now handle multi-world too. After the upcoming RB, the following API changes will occur: onSnowForm will be replaced with onBlockForm. NoteBlock.getNote() that returns a byte will be changed to getRawNote() NoteBlock.getNote() will then be changed to return a Note instead. We're still working on this RB so there might be more to add to this list, but mostly it is the Portal event revamping we're doing.