Google

Android 5.1 has made its first official appearance, though somewhat out of the blue.

The update to Android 5.0 Lollipop is now available on Android One devices, according to the Android One website. Although Google hasn't officially confirmed 5.1's availability, the site specifically touts the latest update with the tagline: "Introducing Android One. Fast and responsive smartphones running the latest version of Android, Lollipop 5.1."

The page promotes a few improvements in the latest version, including up to two times better performance, longer battery life and new settings that can conserve your data usage.

The mention on the Android One page follows a report that the update to Lollipop has been seen on Android One devices shipping in Indonesia, blog site Android Pit said on Wednesday. Sources told Android Pit that Android 5.1 was due out the end of February. So the update appears to be ahead of schedule.

Google did not immediately respond to CNET's request for comment.

Released last November, Android 5.0 Lollipop ran into technical issues on certain devices. Google had to fix some glitches in the new OS running on Nexus devices, prompting it to release Android 5.0.1 and Android 5.0.2. Android 5.1 appears to add or resolve several features, according to Android Pit. Perhaps the biggest change is the return of silent mode, which stifles any sounds and vibrations from the device. But the change log picked up by Android Pit points to a variety of other tweaks: