The mobile update, currently only on Google Play, includes a training area where you can try out all the weapons and practice your shooting skills. There's a new setting for dusk, as well. The big deal, though, is a new Arcade Mode, which drops 28 players (instead of the more typical 100) into a smaller space to fight it out in a faster, more furious scrum. There will be more weapons on the ground, but they'll be limited to one of six types per game: Shotguns, Sniper Rifles, All Weapons, Melee Only, Pistols and Item Heaven.
Finally, there's a "follow" option in the game lobby, according to Pocket-Lint, which gives one squad member control of the time and speed of the dive at the start of each match, meaning you'll all land together as a team, which could make squad games more focused.
As for the desktop addition, adding a map selector to PUBG matches wasn't easy, according to a developer blog on Steam. The team wanted to make sure any changes wouldn't increase matchmaking times, and that players in different regions would be served well, too. The developers gathered feedback from all over the globe and analyzed tens of millions of matches to make sure map selection wouldn't break things for anyone.
When you see it in-game, you'll just need to select the map or maps you want to play. If you choose more than one, the game will randomly select a map to drop you into; you won't get onto any maps you don't select, either. The feature is almost complete, said the developer, and will release soon once it's been implemented on the test servers.