Okay, I'm going to try and explain this the best way I can, PartyZone is not planning on updating the server right now. (But that doesn't mean it won't update in the future.) If we'd update the server, we would lose a lot of players. Now, you might think, "But that's impossible! Players would love to build with the new blocks etc." but there are indeed reasons why I am saying this. The majority of our players still use versions lower than 1.9, because a lot of their favourite (popular) servers still run on those versions. Let's say there's a very popular server called, 'Block World', with 11400+ players playing at once. Now, Block World runs on 1.8.9 and most of the games they have, are only playable for players using that specific MC version. So, of course players would switch their version to 1.8.9 just to play the games. The thing is, PartyZone doesn't have that many players that will switch their version just to play games like Murder and Splatter because a lot of our players do indeed play on Block World and other popular servers. They won't update their version just because we told them to. They would rather change their version once Block World etc. update their server's version.
So what I'm trying to say is, PartyZone can't update to 1.12 until other, larger servers with a larger playerbase updates theirs'.