If you have lost the source code for a project you own, the most reliable path is often to contact ionCube support or check your own version control history. While there are paid professional services that specialize in bytecode restoration, these are rarely free and usually require proof of ownership to ensure that the service isn't being used for software piracy.

It is important to understand that ionCube is not just simple encryption; it is compilation and obfuscation IonCube php encoder [duplicate] - Stack Overflow

If you truly need to decode an ionCube v10.x file to run on PHP 5.6, you have limited options. Let's separate fantasy from reality.

The Reality of ionCube v10 Decoding for PHP 5.6: What You Need to Know Looking for a free ionCube decoder v10 for PHP 5.6