Considering that the Lollipop update for these devices took more than 3 months to land, it is pretty surprising to see the company roll out the update on the same day as its flagship Nexus devices.
The link to the 337MB OTA update has been captured, so if you have not already received the update on your device, you can always manually sideload it.
The update does not seem to be available for the second generation Android One handsets, but it should not long before Google rolls out the Marshmallow update for them as well.
Android 6.0 Marshmallow brings with it a number of improvements including a permissions manager, App standby, Doze, and fingerprint scanner support.[Via XDA]