Rather than searching for an IonCube decoder for v10.x and PHP 5.6, the best long-term solution is to migrate your code.
If your server must stay on PHP 5.6 for other reasons, isolate the problematic application:
The IonCube Loader is the runtime counterpart to the Encoder. This PHP extension is installed on a web server and works within the Zend Engine. When PHP encounters an encoded file, the Loader intercepts it, decrypts the bytecode, and passes it to the PHP engine for execution—all transparently to the end user. This approach uses a stack-based virtual machine and integrates deeply with the Zend Engine's internals. ioncube decoder v10x php 56
If it sounds too good to be true, it is. No legitimate online service can decode Ioncube v10 files for PHP 5.6.
Several services, such as UnZend or Decodez, provide "ioncube decoder" services. Easy to use, fast. Rather than searching for an IonCube decoder for v10
The Evolution of PHP Deobfuscation: Understanding the ionCube Decoder v10.x for PHP 5.6
Ioncube versioning can be confusing. Version 10.x (released around 2017-2018) introduced major changes: When PHP encounters an encoded file, the Loader
: Websites like Deobfuscation offer paid services to decode various versions of ionCube (including PHP 5.2 – 5.6).