I have an iPhone 4S, 16GB, and not jailbroken. I wonder if upgrading to iOS 7 will delete everything (apps, pictures, videos, and messages) on my phone.
Does updating to iOS 7 delete everything on my iPhone?
No it will not!
No it won't, your data will be safe, although you could back up important pics and stuff on iCloud if something happens
No, but to be on the safe side you can backup you data
No it will not.