https://www.gamespot.com/articles/new-rainbow-six-siege-update-rolling-out-patch-not/1100-6457531/

Rainbow Six Siege received a major update, Chimera, in early March to kick off Year 3 of the game. The first patch since then is now rolling out on PC, with a PS4 and Xbox One release to come later this week. Unlike the Chimera update, however, this one deals primarily with fixing things, rather than introducing new content.