Ark's next patch, v257, was due at the end of April, but it's been pushed back to May 3 both to give Studio Wildcard time to finish their work and so players can move any bases or structures they've built inside the dormant volcano. The volcano, see, is going to receive "an active remodeling" which I presume means a bunch of lava is going to start flowing.
Any player-made structure within the highlighted borders (see image below) is toast, so grab the nearest Quetz and get packing. A small client-side patch was pushed out today that displays the borders in-game as well, so you'll be able to tell which structures are in the danger zone.
The patch, when it does arrive, will also bring four new dinos (including a giant bee), new Tek features (including a cloning chamber) more UI changes, hairstyles, and new music tracks.
Also coming: "Ascension" game progression, which sound like end-game systems and bosses. This post by Jat on the Steam forums sums up the Ascension process rather succinctly:
"It involves beating all the bosses, going into the volcano, completing an uber-hard dungeon and travelling through a stargate, beating a final fourth boss and discovering the true nature of the ARK, sacrificing your character and resurrecting as a new character containing a soul cube with a progressively level cap (and if done again, taking on bosses that are scaled even more difficult and have some changes each time). That about cover it? ;-)"
That about covers it.