Between Minecraft versions, the VoxelShape (collision box and outline) has changed. Although they are mostly compatible, things such as iron bars and glass panes have made changes which may trip the server's anticheat as the player is considered to be 'cutting through' the block

I'm not sure what the best place to get a full list of VoxelShape changes would be, without making some mod for each version to dump them all. But this is definitely within the scope of multiconnect.

Will fix #110