Conference room show displayname instead of AD account names

I have AD ldap setup. Everything seems good. I have ldap.namefield set to displayname. User roster shows me display name instead of AD username which is great… However in a conference room all I see from other users is their AD username instead of display name. I show myself as displayname. Is there something else I need to set or do to see other users display name in the conference room?

Clients usually have a separate field for group chats - Nickname. Some clients ask to provide nickname when joining a room (Gajim) and as default put username in there. Spark doesn’t ask for it and also uses username, if Nickname field is empty in its profile. Clients don’t know what display name is set for the user on the server, they only know its username. At my last job we used to work around this by manually setting Nickname to the same display name when first running Spark. Of course, we had to change it when name was changing. I don’t know if it is possible to set Nickname field with LDAP.

I have created a ticket for Spark, although there are no developers working on it currently https://issues.igniterealtime.org/browse/SPARK-2105