https://wccftech.com/one-ui-beta-4-is-officially-rolling-out-for-samsung-galaxy-s21-series-in-september/

Samsung is gradually working on its pace to release the latest software updates for its userbase. Google's Android 12 currently rests in the beta phase and is available to smartphone OEMs to tinker with according to their platform's need. Now, the Android 12 based One UI 4 beta will soon be available to Samsung's Galaxy S21 owners. Samsung has confirmed today that One UI 4 will be available to Galaxy S21 series users in September.

As mentioned earlier, Samsung has confirmed in its community forums that the Android 12 based One UI 4 beta software will be available to Galaxy S21 series users in September. Take note that the exact release date of the platform is not mentioned at this point, the company does say that the beta program is "coming soon!"