https://wccftech.com/galaxy-s21-may-2021-security-update-now-rolling-out-with-improved-camera-and-quick-share/

Samsung users are enjoying great software support. We can finally say that Samsung has finally sorted their hardware and software; both aspects of these devices are on the top of the game. Samsung was one of the first OEMs to release the April 2021 security patch to numerous Galaxy devices. The company has stepped up once again; a plethora of Galaxy S21 users worldwide are reporting how the May 2021 security patch is now rolling out to their devices.

Twitter user @AdamleeTs92 posted a screenshot of the Galaxy S21 Ultra receiving the update. Based on the screenshot, you are getting several improvements, including better camera performance and better performance when using Quick Share. The update weighs a substantial 1.14GB, so you should download it on your Wi-Fi.