UPDATE: The temporary worlds have now all been reset!
The temporary worlds (Mining World, Nether and End) will be reset at some point next weekend (27th-28th June); this likely to result in a very short period of server downtime next weekend while the reset occurs. As is currently the case; the spawns will continue to change constantly in those worlds, but the reset means further fresh areas to explore.
Please ensure that anything you wish to keep from those worlds is removed before next weekend.
A further reply will be made...