Upgrading Bugzilla to 2.18.6 brings in MySQL 5 as well - but MySQL 5 is not supported with Bugzilla 2.18, as MySQL 5 changes the syntax for some commands and there is no plan to support this in the 2.18 bugzilla line. This is explained more explicitly in the MySQL and Bugzilla bug databases: MySQL: http://bugs.mysql.com/bug.php?id=16029 Bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=307091 Solution: either provide a patch for 2.18 which supports MySQL 5 or don't upgrade MySQL at the same time as Bugzilla.
*** This bug has been marked as a duplicate of 155340 ***