Based on recent correspondence, it looks like Mailman, a very widely used mailing list management utility, will be EAI Ready by the end of the year. Here’s some relevant extracts from recent correspondence: Mailman is written in Python and that is an important fact for understanding the way forward. “I understand that the SMTP library for Python 3.5 already has EAI support. However, the most current release of Mailman (Mailman 3.0.3) does not work with Python 3.5. We have gotten confirmation for the Mailman development team that they will transition to Python 3.5 as part of the Mailman 3.1 release. We are told that Mailman 3.1 is scheduled for release at the end of this year.” “Some production installations that are running Mailman 3.0.3, but they have to install to from the source code in git. The developers are taking a lot of care to ensure that is doesn't break. Here's a write-up from one of the python.org administrators on the work he did to stand that up: https://wiki.list.org/DOC/Mailman%203%20installation%20experience In addition, there is a dedicated Mailman 3 user's list if you want to see the discussion among the folks that are trying to make use of Mailman 3 as it gets developed: https://lists.mailman3.org/mailman3/lists/mailman-users.mailman3.org/ Don