Small possible hack, if actually you hate Sailfish X that much and long for your N900 that much : Run WhatsApp on alien-dalvik on the Xperia. On the N900, browse to web.whatsapp.com Follow the onscreen instruction to connect your N900's browser to the WhatsApp running on you Xperia. Voila, you have WhatsApp on your N900 (keep the Xperia plugged in the charger, though : web.whatsapp.com needs constant connection to WhatsApp and the Xperia going to deep sleep would break the connection). For a video tutorial look for "how too hack your boyfriend/girlfriend whatsapp" on youtube there are dozens of videos (WTF, internet ? Is stalking your significant other to check if they cheat the only use you've found with that function ? What's wrong with you, internet ?)