: Your console will prompt you to download the update before launching the game while connected to the internet. Manual Downgrade to Update 84 (Advanced Users)
: 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. subnautica-update-84-installation-tutorial
For a visual walkthrough on how to access and install specific legacy versions of the game, check out this guide: : Your console will prompt you to download