Several customers reporting the same issue. Tested the build above - no go. Rolling back to SM 16.3.6705, soon as peak mail time slows...
Another customer/reseller commented to us today - I think we will just quit trying to wait for SmarterMail to work out these issues and go to Outlook.com...
>:(
Matthew J. Sine, General Manager8Dweb LLC
"Making the Web a Happy Place"