Folks getting their Nexus 5X in the mail are seeing a prompt to install a small 42MB update. This update will bring your Nexus 5X’s build number up to MDB08I. Unfortunately, there’s no word on what this update brings to the device.
It’s likely just a small update to fix up some holes before the masses started receiving the device and nothing more. However, some users over on Reddit are claiming that this update enabled VoLTE on T-Mobile for them.
If you haven’t received the update yet, be sure to head into your Settings menu and check manually!