https://www.gamespot.com/articles/heres-when-rainbow-six-seiges-big-operation-chimer/1100-6457167/

Rainbow Six Siege is getting a big new update, called Operation Chimera, very soon, which adds new content and changes existing characters, weapons, and maps. Today, Ubisoft announced that it'll roll out the patch to all platforms tomorrow morning.

On Twitter, Ubisoft stated that each version of the game will go down for an hour as the company launches the update. It'll arrive first on PC, which will be down from 6-7 AM PT / 9-10 AM ET / 2-3 PM GMT. Next, the PS4 version will go down for maintenance and deployment from 7-8 AM PT / 10-11 AM ET / 3-4 PM GMT. Finally, Ubisoft will deploy the update to Xbox One from 8-9 AM PT / 11 AM-12 PM ET / 4-5 PM GMT.