iOS 9 will delete apps to make room for system updates
 

Early adopters of iOS 9 beta 2 have discovered a new feature that will temporarily delete apps from overloaded devices when there isn't enough space to install system updates. Many users with the smaller 8GB and 16GB iPhones reportedly had difficulty...

http://www.engadget.com/2015/06/23/i...=rss_truncated