I was able to silently install the plugin using this command:
\\server\share\CiscoEmailSecurity-7-5-2-009.exe /exenoui /qn
However, it has unwanted default options applied.
I need to silently install it to Outlook 2016 clients, but I need the following options set.
1. Do not enable encryption plugin,
2. Do not enable sending anonymous usage data to Cisco.
How do we do a silent install with these option set?