cPanel & WHM 11.52 is set to reach End of Life at the end of September, 2016.
In accordance with our EOL policy ( https://go.cpanel.net/longtermsupport ), 11.52 will continue functioning on servers where it is already installed. However, no further updates, such as security fixes and installations, will be provided for 11.52 after it reaches EOL.
We recommend that all customers migrate any existing installations of cPanel & WHM 11.52 to a newer version (either 56 or 58).
If your server setup complicates the process of migrating to a newer version of cPanel & WHM (an upgrade blocker list is available at https://go.cpanel.net/blockers ), then cPanel is here to help. Simply open a support ticket at https://tickets.cpanel.net/submit so that our knowledgeable support team can provide recommendations, migration assistance, and more.