Dear folks, First, my environment is I have two iPhones with the same Apple ID signed in, with updated whatsapp version but different phone numbers. All my iOS version is 10.3.1. I am trying to migrate the chat history from my old iPhone 6s to iPhone 7. During restore, the original SIM card is put into iPhone 7 but I put another active SIM card and completed the change number process. The issue happened after I restored my 6s' whatsapp backup to my iPhone 7. After successfully restore from iCloud, when I try to use the iCloud backup feature of whatsapp, it seems halt around 94% (292.6 mb). I tested and isolated this is my network issue. It did not reproducible on my original iPhone 6s. I am a bit hesitant to delete the original backup on iCloud, as a fact I wonder if it is related to same Apple ID. May I know 1. If I have 2 phone numbers but one Apple ID, can I backup/restore all whatsapp' backup per phone number? So how whatsapp determines which backup when I tried to backup/restore on iCloud? 2. Is it possible be the iCloud performance? (In fact, I don't know if the backup is to whatsapp's server or iCloud) 3. Is this a compatibility bug among whatsapp and iOS 10.3.1? Any help will be appreciate your prompt response.