The Samsung Galaxy A51 announced last December with Android 10-based One UI 2 is getting a new software update which brings in One UI 2.1.
The new build also includes the April 2020 Android security patch and comes with improved AR Emoji, Quick Share, Music Share, and updated Gallery app and Samsung Keyboard. However, the update doesn't bring all One UI 2.1 features to the Galaxy A51.
The new firmware sports version A515FXXU3BTD4, requires a download of around 1.25GB and is currently seeding in Afghanistan, Egypt, Israel, Russia, South Africa, Kenya, Morocco, Saudia Arabia, Turkey, and Pakistan.
The update is rolling out over the air and should reach your Galaxy A51 in a few days, but you can also check for it manually by heading to the Settings > Software update menu on your unit.