XDA editor-in-chief Mishaal Rahman said that Google plans to announce the AOSP (Android Open Source Project) version of Android 12 on October 4. Since the company often releases a complete public version at the same time as the release of AOSP, this means that Pixel users may start to get an upgrade from that day.
This may also be the release time of the Pixel 6 series. Google usually does not release new phones before Android 12 is released, so the Pixel 6 series may be on sale in late October. If you are not using a Pixel phone, you need to wait for the manufacturer to follow up.
Although some mobile phone manufacturers tend to release major Android system updates very quickly within a few weeks, many other mobile phone manufacturers take months. Samsung did not start deploying Android 11 until December 2020, three months after Google officially released the operating system.