Following H1Z1: Just Survive's recent renaming to Just Survive, I suppose it's not a huge surprise that Daybreak's battle royale shooter H1Z1: King of the Kill is now simply called H1Z1. In past interviews I've conducted with members of Daybreak and pro players, everyone pretty much just calls it H1Z1 anyway so it makes sense.
The name change may also suggest that H1Z1 could be preparing to leave Early Access, but Daybreak isn't giving any specific details on that yet. From a post on the official site:
"To answer the question many will have: does this mean you’ll be exiting Early Access soon? These updates definitely take us a step closer, but we still have to polish up the core gameplay (with your feedback) before we’re ready for a full launch."
Along with the name change, the UI is getting some tweaks "that simplify the menus and update the game’s look" that you can check out on the test servers before they're officially rolled out, which is planned for October 18. And, H1Z1's annual Invitational tournament is happening on October 20-22, at TwitchCon 2017.