According to the Sammobile report, the October 2021 security update for Galaxy A31 comes with the firmware version A315GDXS1CUJ4. It is reportedly rolling out in various regions, including Argentina, Brazil, Chile, Colombia, Guatemala, Dominican Republic, Ecuador, Mexico, Panama, Paraguay, Peru, and Uruguay. Samsung Galaxy A51, on the other hand, is receiving the new OTA update in various Asian markets, including India, Nepal, Russia, and Sri Lanka. The update tags along the firmware version A515FXXU5EUJ2. The update might bring device stability improvements and some general bug fixing.
Samsung Galaxy A31, Galaxy A51 users in the specified regions have started picking up the new software update. If you have not received it yet then manually update your phone by navigating to Settings » Software update. Both Galaxy A31 and Galaxy A51 were launched over a year ago with Android 10 pre-installed in it. Thanks to a major OS upgrade rolled out earlier this year, both the devices are now running Android 11 OS with One UI 3.1 skin at the top. Samsung has also started testing the Android-12 based One UI 4.0, which is rolling out as a beta update to the Galaxy S21 series. The Galaxy A31 and Galaxy A51 are likely to receive the Android 12 upgrade, as per the company’s software update policy. [source 1, 2]