So I circled back to this last week and installed nethserver-horde on my Neth 7.4 server, and it seems to be working pretty well. One oddity I’m noticing, though, is that I need to log in twice to get into imp–even if I go to domain/horde/imp, I need to enter username/password twice, whereupon I’m taken to the mailbox and everything works fine. Has anyone else noticed this?