Features including "Steam Community, in-game matchmaking or lobbies, downloading games from Steam content servers, and making purchases" will be offline during the maintenance, which will begin at 6:00pm PST and is expected to last up to three hours.

Valve explains "games that do not rely on Steam matchmaking services should remain playable," though you'll have to face the zombie apocalypse alone for a few hours.

Valve recently revealed that its digital distribution platform experienced a 205% growth in unit sales last year and now has over 25 million "active accounts."