[CentOS] OS upgrade from CentOS 6.x version.

Hi,

Currently I am running CentOS 6.4 on all my production environment. Lets
say after six months there is CentOS 6.5. Do i need to update it to the
latest version and is it recommended to use yum update command to update to
6.5 on a production environment without testing. Please help me understand.

Regards,

Kaushal