PHP 8.1 INTERNALS UPGRADE NOTES
1. Internal API changes
+ a. Removed Zend APIs
2. Build system changes
========================
1. Internal API changes
========================
+ a. The following APIs have been removed from the Zend Engine:
+ - The spl_ce_Aggregate, spl_ce_ArrayAccess, spl_ce_Countable, spl_ce_Iterator, spl_ce_Serializable,
+ spl_ce_Stringable, spl_ce_Traversable alias class entries have been removed in favor of zend_ce_aggregate,
+ zend_ce_arrayaccess, zend_ce_countable, zend_ce_iterator, zend_ce_serializable, zend_ce_stringable,
+ zend_ce_traversable.
========================
2. Build system changes