Please, let’s limit this thread to useful information about this particular release. No "Me too", "Not me yet", or "When will I get it?" posts, please.
Firmware update G998U1UEU4AUI7 is now available for the G998U1 (US unlocked S21 Ultra). You can get it OTA from some carriers, or download it manually from Frija. It does not include a new security update; like the previous (AUH9) firmware, AUI7 is still at the Sept 1 security patch level. (As always, if you want to know if your carrier has released it OTA yet, you can check Sammobile.com, or your carrier’s website, for a usually almost up-to-date report.)