The taste is great, as they reported, except one intolerable problem that they lose contacts, photos, messages and other multimedia files by upgrade Lollipop to Marshmallow.
Via Wi-Fi Direct: Tap on “Wi-Fi Direct”and select the device to which you want to copy the contacts.
These are two ways to upgrade Android from Lollipop to 6.0 Marshmallow available at the moment.
Hope you do a secure update with the help of Ease US Mobi Saver for Android and a complete update with the guide introduced above.
Note that this process is only for advanced users, and better on Nexus devices. Download and install the latest Android SDK on your Windows computer; Step 2.
Add the SDK folder to the path: My computer Environment variables; Step 3. Download the factory image for your device on your Windows computer and connect your Android to the computer via USB; Step 5.