Deprecated features in PHP 7.1.x

ext/mcrypt

The mcrypt extension has been abandonware for nearly a decade now, and was also fairly complex to use. It has therefore been deprecated in favour of OpenSSL, where it will be removed from the core and into PECL in PHP 7.2.

Eval option for mb_ereg_replace and mb_eregi_replace

The e pattern modifier has been deprecated for the mb_ereg_replace and mb_eregi_replace functions.