Upgrade iPhone 4 to run iOS 9
114387
How do I upgrade an iPhone 4 from iOS 7.1.2 to iOS 8 or 9
99290
How to check iOS version?
29191
Upgrade to 18.04 from 17.10
76890
Can I restore data backed up from a newer version of iOS?
71532
How To Make iPhone App compatible with multiple SDK (firmware) versions
102248
How do I upgrade my iOS on my iPad 1st generation?
48939
How do I install an older version of an app on an iPhone?
140542
What does the fourth number in the release version mean?
342
Iphone 4 won't update past a 7.1.2
135547
Downgrading from OS X 10.9.2 to 10.9
44028
Unlocking iPhone 4
50897
Download older version of Xcode?
2196
How to reinstall old iOS software?
99681
What filesystems does iOS use?
8359
How do I migrate my existing Apple Notes from iOS 4 into Simplenote, Evernote, or some other notes app?
85188
Is it possible to update any iOS 6 device to iOS 6.1.6?
1520
How to install software or upgrade from an old unsupported release?