Greetings...

Anyone know, please, if the IMP/Horde add-ons produced by them and third parties (especially the DNSBL related and anti-spam stuff) work correctly on Cpanel?

Many thanks

From speaking with Cpanel you are very limited on what you can do with Horde serverwide. If you are willing to maintain the updates after eacy /scripts/upcp then you could add some of the nicer features. Also, note that Horde uses a master DB for your entire server which means you cannot backup and restore individual users settings or move them to another server. We have taken the policy that Horde is supported in only its basic form, but have made it so users can install their own versions.