In previous Mac OS X versions (to El Capitan), you could administrate mail server settings in the app called Server Admin. In El Capitan, all I have access to is the Server.app. In there are only very limited settings for the email server.
We are now in the process of leaving this in-house email server for Office365 and Exchange. In order to migrate all user emails from our server to the cloud servers in Exchange, we need to increase the maximum number of IMAP connections allowed.
I can't seem to find where to do this? Server Admin could do this but that won't work in El Capitan. Any ideas?