Google has just announced and released the biggest Lollipop update yet, Android 5.1. The Android 5.1 Lollipop update comes with new changes and newly introduced features. Different parts of the Material Design user interface have changed like status bar icons and added quick toggle settings for Wi-Fi and Bluetooth.
Improvements have been made on other departments too. Android 5.1 finally supports multi-SIM and HD voice capabilities, and there have been improvements to the Priority Mode. Overall, Android 5.1 is a great update and if you have a supported phone, you should update.
At the moment, not all devices have the luck to be officially updated to Android 5.1 Lollipop. However, good thing that there are custom ROMs to keep us busy. Custom ROMs like CyanogenMod have been already updated to Android 5.1 Lollipop (CyanogenMod 12.1) and other ROMs are doing the same thing.
If you happen to install a custom ROM based on Android 5.1 Lollipop (AOSP, CyanogenMod or stock-based), you will also need to download and flash Google Apps (Gapps). Gapps are a must for every Android device. They contain the Google framework (Google Services Framework) that allows all Google apps to work properly like YouTube, Play Store and other Google Services.
Android 5.1 Lollipop requires new apps and it is better to install Android 5.1 Gapps that Android 5.0 Gapps. The good news is that the package has been released and you can install it right now.
The Google Apps (Gapps) contains some of the most important Google applications like Google System Base, Calendar Sync, Play Store, Search, Calendar, Google Now Launcher, YouTube, Maps, Gmail, Hangouts and more.
Download Gapps for Android 5.1 Lollipop: gapps-5.1.x-20150324-minimal-edition-signed.zip
To flash the package, boot into recovery mode and flash the zip file. Then reboot your phone and enjoy Google Apps.