Can't restore whatsapp chat history?

Ok I have downgraded my iphone 4 to ios 5.1.1 from ios 6.1.3.
I want to restore my whatsapp chat history but itunes says the backups
from ios 6 are not compatible.

I do not care if the actual messages are lost but I want the chat groups to be there.
When I launch whatsapp in ios 5.1.1 it prompts me with the message that if I continue I can't restore my messages at a later date.

So my question is: If I launch whatsapp in ios 5.1.1 without restoring, will it show my old group chats without the actual messages? Or will it be blank and I have lost all my messages?

Additional question: Is there a way to make the ios 6 backup compatible with ios 5 or extract the information from it?

You can't restore any data in whatsapp from the backup. If you update to the new whatsapp version then you will be able save your chats on iCloud. I wouldn't recommend restoring iOS 6 data on iOS 5.1.1. I don't think they are fully compatible with each other