It appears that Arnt Gulbrandsen via UA-EAI <arnt.gulbrandsen@icann.org> said:
Hi,
3.10 still doesn't include EAI support. I think the only reason is that the changes involved are rather large. If I were the Mailman maintainers I'd plan an uninterrupted week to review and merge that, and that's a big chunk of time for a spare-time project like Mailman.
I think the reason is that there is no way to have a mailing list with both EAI and ASCII subscribers because there's no way to downgrade an EAI message and allow ASCII users to reply. We've been thinking about this for a decade and nothing has worked. I suppose you could add EAI-only lists where you could only subscribe from a system with SMTPUTF8 support but that doesn't seem very appealing. R's, John