System Software Corruption comes from three sources. Mostly one source. Simply put, the device requires free storage space to operate. More often than not, this warning message gets ignored many times every day and hundreds of times over the course of weeks and a couple months. Once the corruption occurs, deleting your content is no longer sufficient to fix the problem. To make the device work PERFECT again, it is now required to perform three basic steps; Backup the device to iCloud, Restore fresh software, and download your iCloud backup. Your device will be identical to how it was before and work perfectly.
Problems with apps from the App Store are usually solved by deleting the app and redownloading.
$35 fee - To handle the entire system reload process for you.