The OnePlus 10 Pro launched back in 2022 with Android 12 on board, and has since received three major OS updates taking it to Android 15. Actually, scratch that - the update to OxygenOS 16 based on Android 16 has just started rolling out. It's only available in India at the moment, and arrives over-the-air as build NE2211_16.0.3.500(EX01). OnePlus promises that it will reach more regions and users in the near future.
The purpose of this release is to allow app developers and early adopters to create "even better software experiences". The installation requires flashing a ROM, and if you don't have experience in software development or you expect to use the device as a daily driver, it's not recommended to proceed.