Migrating from PHP 5.5.x to PHP 5.6.x
PHP Manual

Other changes to extensions

cURL

A number of constants marked obsolete in the cURL library have now been removed:

OCI8

Zip

A --with-libzip configure option has been added to use a system libzip installation. libzip version 0.11 is required, with 0.11.2 or later recommended.

MySQLi

A new mysqli.rollback_on_cached_plink option was added to rollback connections put back into the persistent connection pool.


Migrating from PHP 5.5.x to PHP 5.6.x
PHP Manual