https://wccftech.com/doom-eternal-6-66-update-patch-notes-horde-mode-battlemode-2/

Bethesda and id Software teased it last week, and now they’ve officially dropped Doom Eternal’s appropriately-number 6.66 update. This update adds the new Horde Mode and ultra-challenging Master Levels, significantly expands and tweaks Battlemode, offers up a whole bunch of new rewards to earn, and more. Best of all, it’s all free. You can check out an action-packed new trailer for Doom Eternal's Horde Mode, below.

DOOM Eternal Update 6.66 to Release Next Week; Will Include Horde Mode, BATTLEMODE 2.0 and More