If you have the latest version of Google Play Services, then tapping the update button might actually deliver the update to your smartphone.

One of the most irritating aspects of the Android ecosystem is the delay in the rollout of the latest Android update. Unlike iOS where all supported devices receive the update at the same time, the Android universe only ‘gifts’ the latest updates to Google-branded smartphones, that too to the devices that fall into its first preference batch. It seems that the Google is looking to shed this image according to one Google employee on Google+.

According to Elliot Hughes, a Google developer, the ‘Check for updates’ button now actually works for ‘all’ those Android smartphones that ship with Google’s OTA update app. We used the word ‘all Android smartphones’ because this isn’t a platform-side update. If you have the latest version of Google Play Services, then tapping the update button might actually deliver the update to your smartphone.

However, don’t get too excited about this feature as it has a lot of ‘ifs and buts’. You will only get to see the benefit if an update from Google has been rolled out for your model but your device isn’t in the first batch. It will still depend on the carrier to make the update available to your device. And, if you are using a Pixel or Nexus, then you are in for luck as phones with custom interfaces require some time to get the latest updates.

(source)