Igbinary is a drop in replacement for the standard php serializer. Instead of
the time and space consuming textual representation used by PHP's serialize(), igbinary stores php data
structures in a compact binary form. Savings are significant when using
memcached or similar memory based storages for serialized data.
* Drop support for PHP 5.
* Drop support for APC (APC was only available for PHP5 - It is the predecessor of APCu)
* Emit a warning and return null if igbinary_unserialize() is passed more data to unserialize than expected.
* Fix compilation against PHP 7.4-dev. Igbinary does NOT yet properly serialize/unserialize all classes with PHP 7.4-dev's typed properties.
* The serialization format is exactly the same as igbinary 2.x