When it comes to an Android update, the Nexus smartphones are always the priority, but the case is different in the USA, where carriers are only responsible for updating smartphones as per their own convenience. The AT&T Nexus 6 is still running Android 5.1, while the US Cellular and Sprint has updated their Nexus handset to Android 5.1.1. But the wait is now over, and AT&T has started the Android 5.1.1 update for Nexus 6 smartphones.
The latest OTA update version LMY47Z weighing 81MB will need you to connect your Nexus with Wi-Fi for installation process. Since the Android 5.1.1 is rolling-out to fix previously reported issues, you will not notice major changes on your handset, but it is always advisable to keep your smartphone updated with latest software. The 5.1.1 upgrade brings stability improvement, bug fixes, and disables Smart Lock feature when EAS password policy is enforced.
The OTA update is being sent on staggered basis, so it might take several days to hit your Nexus 6. Once your device will be ready for the update and connected to a Wi-Fi network, it will automatically notify you for the new available update.