OnePlus' 7 and 7T lines of 2019 are still perfectly serviceable Android devices and have a place in smartphone history in that they were among the last to feature pop-up selfie cameras for the edge-to-edge displays only attainable via advanced UDC technology otherwise. Nevertheless, they have officially been on Android 11 for the past year and a half now - unless the user in question was involved in the smartphones' Open Beta programs, that is.
Its members have been party to the OnePlus 7, 7 Pro, 7T or 7T Pro's latest builds of OxygenOS (OOS) in a slightly buggy, advance-preview capacity. These users are also now reportedly first in line for the first ever stable versions of the same software.
Then again, it is of course still not based on the Android 13 now wielded by the latest Google Pixel 7 series, but remains OOS 12.1. These 'new' builds for the 7/7 Pro and 7T/7T Pro is rated for a complete UI update over the preceding OOS 11-based version, at least, as well as new Smart Battery Engine algorithms for potentially improved screen-on time; a new dark mode and new-found support for OnePlus' Canvas AOD.
Then again, it only upgrades the devices' security patch level to August 2022; in addition, OnePlus notes it is only available to Indian-market units as yet. Finally, there is no mention of support for the former top-end 7T Pro McLaren Edition as yet.
Source(s)
OnePlus (1) via XDA
OnePlus (2) via XDA