In our configuration, we have altered all our service banners to remove "SmarterMail" from the connection announcement.

The one place we cannot do this is in the webmail interface source code.

We request that the versioning information that is embedded in the webmail interface code be removed. Keeping the copyright in place is not an issue - but make sure it reads "SmarterTools". Revealing that the application is SmarterMail with an actual build number leaves the webmail interfaces susceptible to "internet device databases" like Shodan - where you can literally search for SmarterMail installations and see over 40k of them because of the webmail or service banners. 

The outside world doesn't need to know what you're running - only you as the host need that information.