Oppo has stuck to its update schedule, although that schedule has now gone through several iterations, making it harder to follow. You should probably just focus on the official Oppo community forum latest news.

According to the resources above, the stable Color OS 12 update based on Android 12 is now officially available for the following devices in the following regions:

If your device is on the list, you can go to Settings > Software Update to check if their device has received the update. Since this is a phased update, it may take several hours to reach your unit.

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