[Observium] observium customizations on PHP code

Observium CE 0.14.4.5229 PHP 5.4.4-14+deb7u14 MySQL 5.5.40-MariaDB-1~wheezy-log SNMP NET-SNMP version: 5.4.3 RRDtool 1.4.7

I have modified one source file : /opt/observium/includes/alerts.inc.php

I restarted web server and php-fastcgi ( no opcode cache ), but Observium doesn't see the update.

Is there an internal function caching ? Am I missing something ?

Best regards, Sala