Android O Developer Preview 4 was released last Monday (July 24), and it was a release candidate. Unless any major bugs are uncovered, the final version will come out soon – perhaps as soon as next week.
The Google Pixel and Pixel XL are first in line to get the new major OS version. Still we are not clear about the official name for Andriod O. current front runner seems to be oatmeal cookie.
There is a chance to push back the release as the Andriod N was started to rollout in August 22 last year.