WhatsApp is the only chat application I use and therefore it will be totally sad if I buy this phone and learn that it doesn't support it.
WhatsApp is now compatible with both single SIM and dual SIM Nokia Asha phones
You can read more about that here: http://gadgets.ndtv.com/apps/news/whatsapp-now-available-for-dual-sim-nokia-asha-phones-335795
take another phone of same platform i.e. java but compatible with whatsapp(like nokia x2-01). copy whatsapp app and folder to the memory card of other phone. take out the memory card and put it in nokia asha 205. open whatsapp and it works. if u copied whatsapp from a friend's phone then delete the previous account and establish new account in ur phone(asha 205) and then in ur friend phones. Now both phones are compatiable with whatsapp.
U may encounter the error that ur store doesnot opens. but u can remove the memory card and then use the store.
this would surely work and even i have done the same.
THis method also works with nokia asha 206,200,201.... :-)