If you've got custom options enabled for any of PhpMyAdmin, SquirrelMail or Roundcube, then you'll need a way to maintain those customizations between updates by custombuild.
To do that, you'd simply copy your custom config to the relevant path.
The 3 paths are as follows:
/usr/local/directadmin/custombuild/custom/phpmyadmin/config.inc.php
/usr/local/directadmin/custombuild/custom/squirrelmail/config.php
/usr/local/directadmin/custombuild/custom/roundcube/main.inc.php
Also, the following directory:
/usr/local/directadmin/custombuild/custom/roundcube/plugins
if it exists, will have it's contents copied into:/var/www/html/roundcube/plugins/
overwriting any duplicates. Â This can be used to copy specific files/configs/directories for customized plugins over to the new version.