Sky dimension

The Sky Dimension (otherwise known as the Floating Island Dimension) is a work in progress by Notch. It "performs well, [but] looks ugly". It is now a confirmed update. But, This will not be a update for a while and looks sort of like The Aether Collab But without the new content (maybe)

It is still unkown how one would travel to the Sky Dimension, but the commonly thought ways are to either create a portal to teleport there, (in the same manner as the Nether) or to just climb up high with ladders, stairs, etc. If the latter is true, the that would most likely increase map height, since the islands (appear to be) well above the clouds. But if the other method of travel is true, and the Sky Dimension is actually seperate from the map, it is likely that falling will kill you in a similar manner to falling into the Void.

Gallery
http://imgur.com/a/cvsYW