Not for rollback but when you dload to EMUI 4.0 you need to do factory reset. All data will be gone.

What bug do u have ?

Im not beta tester.

Stay in b321 for long time. End up unlock bootloader and manually flash update to b563 but the version didnt show as b563.

Once flash to b563, do a full restore of my apps, the weird things is i didnt receive notification of my whatsapp or LINE even i whitelist in battery manager.

I will need to open the app then only i can receive the msg.

So i choose to flash to b521, phone show correct version. This time i do not restore my apps, redownload from play store. Everything b to normal.

And yesterday received b563 OTA, downloaded the full package, restart to install b563 full OTA.

So far no issue, but only the battery life. Draining faster than b521.

When tap chrome Browser, its slower response compare to b321.