On 18 Nov 2020, Michiel van der Vlist said the following...
 
 Mv> So I heard too. I haven't encountered any problems myself. Now that you
 Mv> mentionsmtp servers, I have not yet run into an smtp server that
 Mv> supports IPv6...

Google does:

Name:    ASPMX.L.GOOGLE.COM
Address:  2607:f8b0:400d:c00::1a

Our Office 365 tenant doesn't seem to support IPv6 yet.

Jay

... Why can't you lie to the x-ray tech? They can see right through you

--- Mystic BBS v1.12 A47 2020/10/23 (Raspberry Pi/32)