: If your Steam client is open, it will automatically detect the update and begin downloading it. If it doesn't, right-click Subnautica in your Library, select Properties > Installed Files , and click Verify integrity of game files to force an update check.
For a visual walkthrough on how to access and install specific legacy versions of the game, check out this guide: subnautica-update-84-installation-tutorial
If you are looking for Update 84 specifically to maintain compatibility with older mods or for speedrunning purposes, you can manually revert your game version using the Steam Console. : If your Steam client is open, it
If you are playing on a modern platform, the update should be applied automatically without manual intervention. If you are playing on a modern platform,
: Press Win + R and type steam://open/console .
: In the console, use the command structure download_depot . For Subnautica Windows, the AppID is 264710 and the DepotID is 264712 .