[MM3-users] Unknown attribute: max_message_size

If I make changes here: https://example.com/postorius/lists/test2.example.com/settings/message_accep..., I get a warning that the Maximum Message Size field at the bottom is mandatory. However, if I put a number in that field and save, I get "Unknown attribute: max_message_size". That makes sense, since Mark states in https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/message/... that max_messages_size is not exposed in REST.

What to do?

I have Maxking mailman-docker but can easily copy files into the image if necessary.

Thor