OnePlus started rolling out C.15 to the stable track around 10th June 2022, though the forum post isn't live yet. 9-series got the first stable build on 6th December 2021, though it was quite buggy and was met with general disappointment (it was pulled shortly after rollout). We advised patience for those devices, and we're doing the same now too. The first major Android update is almost always unpolished, so maybe wait for a few more bugfixes. 9-series received a total of 4-5 bugfix releases, and people are still complaining about a few things. 8-series & 8T have also received a few bugfixes, but none of them fixed these issues I had:
- Gmail notifications never worked, no matter what I've tried (not everyone experiences this, weirdly)
- Double tapping on the lockscreen doesn't always turn screen off
- USB choice dialog pops up every single time, even though I've already set a default
- Going to the home/recents screen from an app that supports Material You's dynamic colour lags like crazy, regardless of using gestures or buttons
Also, their own forum posts (for other devices) list many "known issues" for the first stable build. We'll wait and see if that's true for the N200 as well.
OnePlus had also posted a short FAQ for OxygenOS 12, which you can check for yourself as it might clear up a few doubts: https://forums.oneplus.com/threads/oxygenos-12-faq-find-your-answer.1519491/. There's a "peek inside OOS12" thread as well: https://forums.oneplus.com/threads/a-peek-inside-oxygenos-12.1529132/.
Changelog for C.15 (first stable OOS12 build for Nord N200)
- [Added] the support of switching between different layouts with a two-finger pinch gesture, intelligently recognizing the best-quality pictures, and cropping the thumbnail based on the content, making the gallery layout more pleasing
OnePlus seems to use almost the exact same changelog for the first OOS12 release (regardless of device or it being stable/beta).
Where can I install stable OxygenOS 12?
You should have already received a notification from the app about the C.15 update. Simply download as you normally would, and follow the installation instructions.