Migrating from PHP 5.4.x to PHP 5.5.x
PHP Manual

Deprecated features in PHP 5.5.x

ext/mysql deprecation

The original MySQL extension is now deprecated, and will generate E_DEPRECATED errors when connecting to a database. Instead, use the MySQLi or PDO_MySQL extensions.

preg_replace() /e modifier

The preg_replace() /e modifier is now deprecated. Instead, use the preg_replace_callback() function.

intl deprecations

IntlDateFormatter::setTimeZoneID() and datefmt_set_timezone_id() are now deprecated. Instead, use the IntlDateFormatter::setTimeZone() method and datefmt_set_timezone() function, respectively.

mcrypt deprecations

The following functions have been deprecated:


Migrating from PHP 5.4.x to PHP 5.5.x
PHP Manual