There is no magic "one-click" software that perfectly reverts an IonCube V10 file back to its original PHP 5.6 source code. True decoding relies on complex reverse-engineering:
If you have files encoded for PHP 5.6 , you must use the ionCube Loader specifically built for PHP 5.6 on your server. 2. How to "Decode" (Execute) These Files
It is highly recommended to use the ionCube Loader Wizard, a PHP script that analyzes your server and tells you exactly which file to use and where to place it.