I came across issues restoring my iPhone 4 backup via iCloud to my iPhone 6s Plus. I changed my primary email address in my Apple ID account a couple years ago. Since some of my apps where purchased with an older email address on my Apple ID account, they are now grayed out on my iPhone 6s desktop. When it asked me for the password for my old Apple ID account, it wouldn't take my password, so I skipped it and hence the grayed out apps. To fix this, I read that I may need to login online to my Apple ID account and change my email address from my current one to my old one temporarily, however, my old email address has been terminated. Do I need to verify my email if I change my primary email in Apple ID? I'm afraid to switch my email and somehow have my Apple ID get stuck on an email address that I can't access any longer. It's really frustrating that Apple ID's are tied to email addresses, instead of a user name. I would have used iTunes to the do restore but I was using an old MacBook Pro with Snow Leopard, which was fine for my iPhone 4, but not for my iPhone 6 since it needs a newer version of iTunes. I do have Yosemite on another Mac but the SSD drive is small and I can't copy over entire contents of iTunes to it (over 60GB apps, 12 GB of backups, etc).