It would appear that this is a bugfix and March security patch.
Initially, as always, this is rolling out to the non-carrier branded, stock Samsung CSC codes first.
The Galaxy S21 Global, Exynos, devices that will receive this update are…
- S21 5G model SM-G991B
- S21+ 5G model SM-G996B
- S21 Ultra 5G model SM-G998B
This latest release replaces the G99*BXXU1AUB8/9 February builds.
It is a FOTA, (Firmware Over The Air), update and you can check… Settings > Software update… to see if it is available for you.
The update = G99*BXXS2AUBB
Download = 238.95 MB
Build date = 24 February 2021
Release date = 04 March 2021
Camera version = 11.0.02.58
One UI version = 3.1
Android Security patch = March 2021
This is the 7th stable update in 36 days