Samsung is on a roll today. After releasing the new security update to the Galaxy Note 20 and the Galaxy S21 FE, the South Korean firm has released the November 2023 security update to the Galaxy S21 series in the US, specifically to the carrier-locked models in the lineup.
Galaxy S21 series gets November 2023 security update in the US
The latest software update for the Galaxy S21, Galaxy S21+, and Galaxy S21 Ultra comes bearing firmware version G99xUSQS9EWK1. This update is for carrier-locked variants of the phones in the US. It brings the November 2023 security patch that fixes 65 security-related bugs found in the previous software version. It doesn't bring any new features or performance improvements.
If you have a Galaxy S21 series phone that you bought from a carrier in the US, you can now check for the new update. You can do that by navigating to Settings » Software update and tapping Download and install. Alternatively, you can flash the new software manually using a computer running Windows OS and the Odin tool. You would need to download the new firmware file from our firmware database for that process.