Google has just extended Security updates deadline for the Nexus 5X and 6P by 2 months. The two-year-old phones were originally slated to get patches till September 2018. But Google’s support page now shows that date is November 2018. Users might get security updates after that but it is not promised.
Google’s standard promise for security patches is three years and 2 years for OS updates. Since the Nexus 6P/5X were launched in September 2015, 2 years have already passed. So, they just barely got the Android Oreo update. And you probably shouldn’t expect any other major OS update going forward. But Security patches are always good to have.
There isn’t any known reason behind Google’s changed deadline but we might know about it if the company responds to sent emails. The latest patch that the Nexus 6P/5X received was the September security patch for the Blueborne bug. The Pixel devices have also been received it and factory images are live too.