Lukáš Čambala There were some problems with iOS updates last year, as the new system always claimed a large amount of free memory, which was a significant problem for many users. Installing iOS 8 and other decimal or hundredth versions required several gigabytes.
During this year's WWDC, of course, Apple he revealed, that in iOS 9 it solved this problem. The ninth generation of the operating system for iPhones and iPads will require "only" 4,6 GB against last year's 1,3 GB. A lot of emphasis is also placed on the developers themselves to optimize their applications so that each device receives only the parts it really needs when downloading updates. That is, if you own a 64-bit device, then 32-bit instructions should not be unnecessarily downloaded during the update.
However, if you are still struggling with a lack of space, Apple has prepared another useful solution. Developers testing iOS 9 noticed a possibility that if you don't have enough space at the moment (when downloading), the system will automatically delete some items (applications) from your iPhone or iPad, and once the complete installation of the system is complete, the deleted items will be downloaded again with original values and settings. Apparently, Apple uses iCloud for this, or has invented a way to upload the original data when the application is reinstalled.
probably the iCloud, where else would Apple upload it
How about if he doesn't delete data or settings, just the application? Don't think it would be more logical.
It was :) And the data wouldn't leave the device, thus more secure.