Can't say that I have a real good answer other than its just a different imap server. I do know that quite a few people on here use it. If you use Dan Brown's horde/imp 3.2.1, there is something that you have to change. But if you use the version of horde/imp that is default on 5.6, you shouldn't have to change anything on horde/imp....I don't think. Or you could just hold out and wait for version 6. Sounds like they fixed the problem that you are having.