In CentOS 6.x the MySQL version supported by the official repository is 5.1 which causes some issues with apps requiring a minimum of 5.5.
We’ve resolved this by adding a new repo (Remi) and running yum install against the new repo.
wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm rpm -Uvh remi-release-6*.rpm
Upgrade to MySQL 5.5
yum --enablerepo=remi install mysql mysql-server
Upgrade to PHP 5.6
yum --enablerepo=remi-php56,remi update php\*
CentOS 7 supports a more recent version of MySQL but CentOS 6 is still in its support cycle and widely thus widely used on our network.
With thanks to http://centos.org