Possibly, when I got my 7 I turned off my old phone which was a 6s and took out the SIM. I then turned it back on once I had activated my 7 to get some info. off it since I always set up my phone as new vs a restore. I "think" once I signed out of my icloud account on my 6s this went away. Try that. I would be willing to bet you still have your old phone too and are signed into the same icloud account on both your old and new phone. Let us know if that fixed yours too.
Well, I signed the iPhone 6s Plus out of iCloud but the problems are still there.
On the iPhone 7 Plus Photo Library is still showing in the list of apps to be backed up (I have disabled it) and I can not enable the iCloud Photo Library as it keeps asking me to upgrade.
The other issue is the new phone will not let me perform an iCloud backup.
Ive tried signing out of iCloud, resetting Network settings, deleting any old backups, etc.
Must say I am getting extremely sadenned by the whole process. I wish I had stuck to my 6s Plus.