Google nexus5 is getting android 5.1 updates

Nexus series is  the special phones series from google. Because of google branding nexus 5 is getting lolypop updates.
Nexus5 which was released back in November  2013 getting updates very early.

Ota updates weighs in at around 24mb carries a build number of  lmy48b.
If you haven't received it yet, you can manually check for it by
heading to Settings -> About -> System Updates on your device.
For those who aren't already aware, the Android 5.1.1 update
isn't a major one, as it is primarily aimed at fixing bugs and
improving performance and stability.
This comes just a few days after the update started rolling out
for the LG G Flex2 in Korea.