Hi there, 

1. At First I would Like to mention Known problem in (SM16) when Configured Exchange in Ms Outlook 2016 in running Windows 10, it will work fine for a few days or weeks, then suddenly it could not find email settings file, and Outlook would ask to restart in "Safe Mode"  I am not sure if any one else have encountered the same issue. But if Configured with IMAP / POP configuration method then I did not had any issues.

I Hope this is tested and addressed / at least not have in SM17 ??

When Receiving Junk / Spam Mail in Email Clients Configured (Outlook 2016/2019) and the email is marked as Spam, it chosen to "Block Sender" it is not taking effect in mail server, unless logged into webmail server and then selected to Block Sender.

There should be Way weather Email Client is Configured as Exchange/ IMPA and selected in the mail client to block Sender it should be blocked at server lever, not inly locally in the email client. 

I am not sure if I and able to properly express the Idea.

Like we have Option / Welcome Email (in Mail-enable) if New Email Account is created, Mail Server Administrator is also able to edit the Welcome Mail Template which is not only useful but also very Helpful for new users, Because if we Have Welcome Email Pre-Configured by Mail Server Administrator with information like how user can setup mail, POP, IMPA, Mail Server name setting instructions, or even like how to configure email on mobile clients. it becomes very handy.