can i upgrade my 3gs iphone to ios5
I currently have version 4.3.5 on my 3gs and I am wondering if it is safe to upgrade to ios5
iPhone 3GS, iOS 4.3.3
iOS 5 is no longer available. You'll have to update to iOS 6.0.1 at this point, and yes, it's safe. Follow the steps under "Update your device using iTunes" here: http://support.apple.com/kb/HT4623. Be sure to back up your phone before updating.