Migrating from PHP 5.3.x to PHP 5.4.x
PHP Manual

Backward Incompatible Changes

Although most existing PHP 5 code should work without changes, please take note of some backward incompatible changes:

The following keyword(s) are now reserved and may not be used in function, class, etc. names.

The following functions have been removed from PHP :


Migrating from PHP 5.3.x to PHP 5.4.x
PHP Manual