We are aware of a couple of issues that will need a hotfix to the server, however some of these still need to be tested before release. In the meantime it is suggested that for single player, you do not visit any dimensions outside the over world (ie dont go to the nether yet) and for server admins, encourage your players to not go to the nether until these hotfixes are resolved. We are going to be adding a new mod tomorrow to fix the issue where the nether is spawning netherrack down at level 0. The intention is that this should be a void world and the changes which will be live in the next 24 hours will make the needed changes. If you have already spawned a nether in your world you can go into your save folder and delete the DIM-1 folder to enable you to refresh the nether. The other 2 fixes are related to a rare crash and a slight command change that will enable admins to auto tab complete the island command. We apologise that these small issues slipped through under our testing radar.