Jira issue originally created by user chroder:
In Doctrine\ORM\Query\Expr\Composite::processQueryPart(), mb_stripos() is used. The mbstring extension should be checked for and fallback on stripos() used, or the requirement on the mbstring extension should be documented.
Comment created by @beberlei:
This was fixed in master, that is now backported to 2.1.x
Issue was closed with resolution "Fixed"