Hello - I am running an 8GB(!) iPhone 4S with iOS 7. I continually keep running out of space, despite purging data/photos. iTunes says I have 2.21 GB of storage listed as "Other". I'd like to delete it. This is as much as I have in Photos and Apps put together! I read that you can effectively delete "other" by first erasing the phone, then restoring from an iTunes backup. My question is: Will this allow me to reinstall iOS7? Or will I be forced to upgrade to iOS 9? Thanks!