PHP 8.1 introduced major internal changes: enums, read-only properties, never return types, and significant opcode restructuring. Consequently, IonCube had to release IonCube Loader version 12.0+ specifically for PHP 8.1. Any older loader (v10 or v11) simply crashes on PHP 8.1.

When searching for a "decoder repack," the user is implicitly looking for a tool that can:

The short answer is: Partially, but not reliably.

PHP 8.1 is a major version of PHP, released in November 2021, introducing features like enums, readonly properties, and Fibers. IonCube has maintained compatibility with PHP 8.1 since the release of their loader version 10.4.x and above.

Crucially, IonCube’s encoding algorithms and bytecode structure change subtly with each major PHP version to leverage new OPcodes and performance improvements. Therefore, a decoder that works for PHP 5.6 will likely fail for PHP 8.1.