SkyBlock has reset and updated! Lots of things have been changed and added, in order to make Skyblock more challenging.
Added the Nether
This is a second island in the Nether with some slightly different game mechanics. Killing certain mobs in the Nether will make them drop nether items (Pigmen will drop Quartz, Blazes will drop Netherbrick and Wither Skeletons will drop Soul Sand). As well as this growing trees will create a gravel and glowstone tree.
Balanced the shop
The shop now only sells things to help you start farms and blocks and items you can't get anywhere else. This is to make skyblock more challenging, and harder to get on /is top.
New Starter Islands
New starter islands have been added built by moumbear. They're much more interesting than the original islands, with more ores and helpful blocks on them.
Kits for the leveling ranks have been added, these are useful tools to help you get started, or if you just need a pickaxe quickly.
Changes to block values on islands
Spawners and beacons count a lot more towards yours island level, iron blocks will also give much more now. (They previously gave the least out of any ore block other than lapis, they now give 3rd most.)