moving Horde, RoundCube and SquirrelMail address books

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http://unix.stackexchange.com – I have moved a domain of mine from one server to another. Both domains use Cpanel. I have moved all mails that were stored on the old server to the new one and this is fine now. Many users use webmail server with one of 3 mail systems: Horde, RoundCube and SquirrelMail. Even moving the /mail folder from one server to the other, all webmail systems have no contacts on their Address Books. My hosting company suggested to go, mail account by mail account and export every address book importing them on the new system, but this method is insane because the domain has hundreds of accounts and I w (HowTos)