Ok I'm testing it but it seem there are bugs, those ones:

- there are no contacts (i synchronized, but still black screen with no contacts)
- i have 2 opened chat (old ones) but because i dont have contacts, i can only see the phone numbers of those 2 persons but not their names

Notice : i already used whatsapp on my old mobile. When I installed this one it asked me to register giving my phone number and receiving a code. Maybe it was not necessary to do so, and thats why it doesnt work?

Sorry if my english is not perfect