Android 5.1 vs Android 5.0 Lollipop Walkthrough: What’s New

Device Protection

With Android 5.1 Google added even more protection for lost or stolen devices. And while this can't be seen in settings, if you have a password, pattern, or PIN enabled, Device Protection will be working for you.

With Device Protection, your lost or stolen device will remain locked until you sign in with your Google account - even if someone erases the device using the factory data reset option in settings. This feature will be available on most Android phones and tablets shipped with Android 5.1 in addition to Nexus 6 and Nexus 9.

Similar to the iPhone iCloud protection, once a pin in set if you factory reset your Android device you'll need to sign into your Gmail account to use the phone. Meaning there should be a lot less smartphone theft, knowing that many Android 5.1 devices will be unusable to the thief.