As of cPanel & WHM version 74, cPanel will begin to deprecate support of SquirrelMail. The reason is that Squirrelmail is no longer updated since last update May 30th, 2013. It could no longer be patched to prevent security flaws. Due to this reason cPanel have decided to deprecate SquirrelMail. Customers are being left with two bundled webmail applications – Horde or Roundcube.