"iOS 8.3 ruined our freedom of controlling data in our installed Apps and Games," writes iFunBox in a Facebook post. "Apple blocked access of the entire sandbox directory of every installed App since iOS 8.3. Previously only writing is block in executable directory. Now we totally lost the control of Apps on our own devices. We are investigating the situation. Before there is a solution, iFunbox will fail to open data directory of any App if the device is not jailbroken."
iFunBox was one of the first utilities to be updated over the weekend with a partial fix, with the latest version 2.95 allowing all apps with "iTunes File Sharing" enabled, such as iFileExpress or VLC player, to be opened for sandbox browsing per usual through the utility. Access to other apps will require jailbreaking. iFunBox 2.95 also allows any music file type, such as MP3, to be imported as a ringtone.
Macroplant has also updated iExplorer to be iOS 8.3 ready for OS X and Windows.
The change does not affect users that jailbreak their iPhone, iPad or iPod touch, as doing so enables OpenSSH to be installed for complete filesystem privileges and command line access. File transfers between a jailbroken iOS device and Mac or PC can still be completed as usual, although keep in mind that no jailbreak is available for iOS 8.3 and downgrading will soon no longer be possible after Apple stops signing iOS 8.2 in the near future.