Extension Categorization
PHP Manual

State

This part lists extensions not intended for the production use - they are either too "old" (deprecated) or "new" (experimental).

Deprecated Extensions

These extensions have been deprecated usually in the favor of some other extensions.

Experimental Extensions

The behaviour of these extensions - including the names of their functions and anything else documented about these extensions - may change without notice in a future release of PHP. Use these extensions at your own risk.


Extension Categorization
PHP Manual