We need chat app like whatsapp. Following features are required..
1. One on one chat
2. Upto 2000 members can be added in a group
3. Noone can view contact numbers of other members of the same group
4. Members of a group can not do one on one chat
5. Whenever admin send message in a group, it must deliver to all but if a member replies to the same message, reply must be delivered to admin only. It means Mr.X can not view the reply of Mr.Y
6. Unlimited copy (maximum 500 times) and paste of same message
7. other general features would be same as shown in whatsapp
8. Push notifications
9. some more small general features....
I have experience in working with xmpp one of the best protocol for instant messaging. It needs some expertise to handle it correctly I think I have enough knowledge to do this app.