The Season 4 PUBG Update is live on PC now, letting you explore the overhauled Erangel map, which has seen changes both subtle and transformative. The first update for the season also introduces the new Survivor Pass, Aftermath, which will feature skins and items from Erangel's history, plenty of balance tweaks, a UI update and more.
The gameplay trailer gives you an idea of how the map has changed, but for deeper dive you can check out the 4.1 patch report below.
Erangel was PUBG's first map, so if you've been playing since the Early Access days, you probably know it pretty well. The broad strokes are still the same in the overhaul, so you won't be lost unless you spend too much time admiring the visual improvement and not enough looking at where you're going.
Take a look at the patch notes here.