I need to read up on this Unity 5x Mixed Mode and what it can do. Looks like I point voicemail only to the old existing Unity Voicemail Off Box Message Store and then Unified users to production Outlook/Exchange.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.