A do-it-yourself fix - -
How to keep SquirrelMail after removal - -
The wonderful folks ("quiet cough") at CPanel said - - "..We understand that SquirrelMail’s faithful fans will not welcome this decision, but we have good news! You can continue to use SquirrelMail after version 78 because cPanel & WHM supports custom webmail applications. Follow our documentation on Integrating Custom Webmail Applications, and get the code from the SquirrelMail website..."