Google has confirmed that it’s Nexus 6P and Nexus 5X phones will get Android version updates till the next year only. After the next year there is no guaranteed Android update to these devices. On its Check & update your Android version support page, Google says that the Nexus 6P and Nexus 5X will get guaranteed updates until September 2017.
With the launch of Pixel and Pixel XL smartphones, Google has already discontinued the Nexus 6P and 5X from its main online store, And also will stop seeding Android version update from next year. On it’s support page Google has clearly mentioned that,
Nexus devices get Android version updates for at least 2 years from when the device became available on the Google Store. After 2 years, we can’t guarantee additional updates.
Coming to the other Nexus devices, Nexus 9 and Nexus 6 won’t get Android version update after October, 2016. That means Android Nougat will be the last Android version update to these devices. Nexus 5 (October 2015), Nexus 7 2013 model (July 2015), Nexus 4 (November 2014), Nexus 10 (November 2014) and Nexus 7 2012 model (June 2014), all these phones have already been put out of the list for any Android version update.
As for the security updates, the company gives additional one year to it’s phones to get security updates,
For at least 3 years from when the device first became available, or at least 18 months from when the Google Store last sold the device, whichever is longer.
Google has also confirmed that it’s newly launched Pixel phones will get guaranteed Android version updates until October 2018. After that, Google won’t have plans to roll out any latest Android version update to it’s Pixel and Pixel XL phones.