It works like this. In the Game Mode selection screen, you’ll see a “play with your friends” panel on the left. Clicking it shows you a list of your friends who are currently playing the game. Upon selecting your friend, you can see their game mode and how long they have until their current session ends.
You can join your friend by pressing the “join” button. The team notes that this patch will only affect newly created games. Additionally, a host of QoL improvements are included in the patch which include gameplay, building, visuals, character, mobs, performance, drop zone, biomes, and bug fixes.
This update comes at a time when the player population continues to decline according to Steam Charts. The average player count as of this writing stands at 104 players, with the peak player count sitting at 554 players. The 24-hour peak as of this writing stands at 36 players.
You can read our impressions of Population Zero here.