If you wanna upgrade it to the newer version without enough space on you iPhone, ipad or ipod Touch, There are 2 ways to clean iPhone junk files: One way to maintain your privacy is to delete cache manually. But you might delete some important files by mistake. Another way is using clean tools such as Mac go iPhone Cleaner: You download it in your computer (it has mac version and pc version). Second,start the cleaner Connect your iPhone to Mac and open this cleaner, just two simple clicks and you can start the clean now. Then, deselect the files that you wanna keep and click on Clean your iPhone button to start cleaning.