SMTPUTF8 in MAIL FROM command

I have one customer that is attempting to send email using Outlook
2016 (I think). Their MAIL FROM command looks like this:

10:09:47.618 4 SMTPI-548278([1.2.3.4]) cmd: MAIL FROM:
<[email protected]> SMTPUTF8
10:09:49.621 4 SMTPI-548278([1.2.3.4]) rsp: 555 syntax error in MAIL FROM parameters
10:09:52.136 4
SMTPI-548278([1.2.3.4]) cmd: QUIT

Is that some standard that we (CommuniGate server users) should be accepting at this point (the SMTPUTF8
string at the end of the command)? I am using CommuniGate 6.0.11 right now, but I can see no mention of the string SMTPUTF8 in the history for
versions 6.0 or 6.1.

According to https://en.wikipedia.org/wiki/Extended_SMTP#SMTPUTF8, one feature of this extension is that email addresses
containing non-ascii characters can be used. However, not many mail servers seem to support it.

Again, looking in my logs, I can see only
one customer attempting to use it at this point.

Anyone else have experience with this?

--

Jeff Wark
Tbaytel
Internet

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