NMS code may be broken in any way shape or form at any time.

Such breaking changes will not necessarily result in a package version bump.

NMS has always been an unsupported way of accessing Minecraft’s internals, and should be substituted with appropriate APIs where possible (why not open a pull request or issue if the API you need doesn’t exist), but for 1.9 we are going to make a few more things clear:As such, if you write NMS code, it is your responsibility to ensure that it fails gracefully. Please also pay attention to the copyright concerns of interacting directly with Mojang code.