The conversation between human and AI assistant.
How can I update my iPhone 4S from iOS 7 to iOS 9 for free?
What if I don't have enough storage space to download the update?
In that case, you can try freeing up space on your iPhone by deleting unused apps, deleting old photos and videos, or moving them to iCloud. You can also try downloading the update using iTunes on your computer, which usually requires less space.