Google has published/refreshed the support periods for its Nexus and Pixel devices. These periods marks the end of Android support.
All support periods has been published at this Google support page, titled as 'Minimum update & support periods'. Here are the support perions for Nexus devices.
(Source: Google)
Older devices up to Nexus 5 are out of support, and support for Nexus 6 and Nexus 9 ends Oktober 2017. The Nexus 5X and Nexus 6P devices will be supported until September 2018. And below are the support periods for the current Pixel handsets.
(Source: Google)
Pixel Smartphones are receiving new Android versions until October 2018, and security updates until October 2019. So it's 2 years for Android updates and 3 years for security updates – to short for Tablet PCs and high end handsets – in my opinion. The only advantage: Google's reference devises are receiving a good LineageOS support. (via)
