cPanel & WHM version 58 will reach End of Life at the end of July, 2017, and will no longer be supported by cPanel except when upgrading to a supported version.
In accordance with our EOL policy (https://go.cpanel.com/longtermsupport), 58 will continue functioning on servers where it is already installed. However, no further updates, such as security fixes and installations, will be provided for 58 once it reaches End of Life.
We recommend that all customers migrate any existing installations of cPanel & WHM version 58 to the most recent version of cPanel & WHM 64, which you can read about on https://releases.cpanel.com.
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.com/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.
For the PGP-signed message, see 58 EOL in 2 months.