Apple just released iOS 8, but if youre preparing to update your iPhone or iPad then be ready to clear out enough free space. While previous iOS updates have always required around 1GB of free space, a large number of iPhone and iPad owners are noticing that iOS 8 requires up to 5.7GB of free space to install. The number varies depending on device and increases up to 7GB on some iPad models, but if you have an 8GB iPhone 5C or even a 16GB iPhone then youre likely to run into issues.