iOS 9 will temporarily delete your apps if you don't have enough space to update
This year, Apple proudly announced that the iOS 9 update will only require 1.3 GB of temporarily free space in order to nest itself on an iDevice. Additionally, Cupertinians spoke about the concept of "app thinning" – developers will now be able to categorize app resources so that each user's device will only download the ones it needs. For example, 64-bit capable iPhones will discard resources that are meant for the app to run in 32-bit mode, and vice-versa. This all speaks of Apple working towards maximizing the usable storage on their mobile devices (and, sadly, it suggests that the company doesn't intend to increase its minimum storage option if its iPhones and iPads up to 32 GB).
If you happen to be one who has already filled their iPhone to the brim, however, fret not – the company seems to be working on yet another solution for OS updates. Users that are testing out the iOS 9 beta builds, but didn't have enough space to download packages for Beta 2, report that their iPhones offered up a solution. The software would automatically delete apps from the storage, in order to complete the OS update. After the ordeal is over, it would re-download anything it deleted from the App Store – sort of how a new or factory reset iPhone would download all the apps that a certain user has been using up until their most recent iCloud backup. However, this could mean that if one currently has an app that has been taken down from the App Store, they will be unable to get it back - ever. So, use with care!
Are you out of storage on your iPhone / iPad?