Google has quietly released Android 5.1 "Lollipop," which means that updates will be winging their way to Nexus owners soon. Everyone else, well, don't hold your breath.
There's no official announcement as yet, but Google's Android One page refers to the new release. Since there's no changelog yet, it is unclear as to what this update brings, although the general consensus is that this is a bugfix release to tackle battery and stability issues.
A leaked changelog from back in December 2014 indicated that the update would include the following:
If you're running a Nexus 5, Nexus 6, or Nexus 9, then Android 5.1 should be headed to your device shortly. If you own something else, then don't hold your breath.
See also: