So, i'm just trying to understand...

The 3-digit-code has nothing to do with our password ?
Password is ( or was? ) md5(strrev(‘IMEI’)) ?
Username: ok, that's obvious

There can't have been many changes to username and password, i guess, we all are using the same as in may (never had to reregister), but i always wondered, why so many people reregistered again... (flashing phone? or other reasons?)

What about providing the possibility of editing username and password in Wazapp-Account, so that you just have to fill in your number and md5(strrev(‘IMEI’)) and you're back again without having to register again?

Just a thought, maybe i'm completele wrong...