There are supposed to be four developer preview updates, followed by the final version in Q3 2017. So, we’re looking at a fall release for Android O. At that time we’ll find out what the version number and code name are. The update will roll out to Google devices within a few weeks, but OEMs will take at least a few months to get their updates out the door. Anything released in 2017 will be first up, followed by 2016 devices a bit later. Anything older than that, and an update will be very delayed or simply not available.