Samsung recently started updating Galaxy S21 smartphones to One UI 3.1.1, and now the firmware has been released for past models.
The system has been released for the Galaxy S10, Galaxy S20, Galaxy Note 10 and Galaxy Note 20 lineup with build numbers G97xFXXUCFUH3, G98xBXXU9DUH2, N97xFXXU7FUH3 and N98xBXXU3DUH2 respectively. Depending on the model, the firmware weighs from 623 MB to 927 MB. The software has been updated with the August Google security patch, which closes some vulnerabilities of the system and includes some new features. For instance, the developers added the ability to quickly enable Bedtime Mode. In addition, the firmware has improved the camera, smooth animations, fingerprint scanner speed, and heat management.
When to wait
As usual, OTA updates are distributed in waves. So you'll have to wait a bit for the firmware to reach your device.