I Have the same issue , i have an iphone 5 and after i updated the iOS 8 , it deleted all of my apps , and whatsapp was one of them, and when i re installed it , i had this page saying i have to restore my chat history form icloud or else i will lose all my datas and then it was written below ' restore chat history' in blue and when i clicked on it , it says fails to restore chat history. And then it says retry or cancel and when i clicked on retry it still fails so i clicked on cancel and the blue line saying ' restore chat history' turned to pale grey saying instead ' chat history is restored ' so what is this , i dont want to risk it and click next on the right up there in the page. And after contacting whatsapp support they replied saying '
'Unfortunately, in-app backup for WhatsApp does not work in iOS 8 at this time. This will be fixed in a future version. We appreciate your patience.
In the mean time, your WhatsApp will be backed up in the back up for your whole phone if you use iCloud or iTunes.' We need any solution for this problem please help.