What about SMTPUTF8

[liaguh]

No description provided.

[Synchro]

More info?

[Synchro]

I had a quick look into this; there are not really any mail servers that implement it yet, let alone testing tools, and judging by this interesting thread, it's unlikely to change any time soon. We can revisit it if it takes off... This series of articles is also interesting.
In the mean time, we could do something related to spotting unicode domains and integrate punycode.

[c-schmitz]

hm.. Any chance on gettting this re-opened? Postfix supports it since v3.0 - please see https://www.postfix.org/SMTPUTF8_README.html

[Synchro]

I would love to do this, however, it's really going to be a bit painful with the current internals of PHPMailer; it could really use a fairly substantial rewrite to permit SMTPUTF8 and a whole load of other things like arbitrary MIME structures and more reliable DKIM. I have had thoughts of doing this for some time, but it's a very big undertaking. Some of the things I was thinking about can be seen in the dev branch of the DKIMValidator I wrote (which bears very little resemblance to what's in its main branch!), but it's not in a usable state.