By the Email Address Internationalization (EAI) Working Group

The UASG’s most recent evaluation (UASG030A), conducted by Standcore LLC, has expanded testing of Email Address Internationalization (EAI)-readiness among global email systems to include seven additional providers. EAI enables email addresses with either the domain name or mailbox name in any language and script to work properly when sending and receiving emails. The additional software packages tested include Dovecot, Halon, Mailchannels, Mozilla Thunderbird 89 Beta, Sendmail 8.17 Alpha, Spamassassin, and XgenPlus/Spamjadoo. Further, new tests were added to determine whether the systems’ spam filters handle EAI mail. This evaluation is an extension to UASG030, which tested more than a dozen systems and identified a handful – Apple iOS 14, Coremail, Courier, Exim, Postfix, Roundcube – with positive EAI-readiness.


Testing was divided into five groups: Mail User Agent (MUA), Mail Submission Agent (MSA), Mail Transfer Agent (MTA), Mail Delivery Agent (MDA), as well as Spam Filter (SPM). The spam filter tests were new to this evaluation and focused on two styles of filters – a filtering proxy, which provides a mail exchange filter that first receives mail, filters it for spam, and then relays the filtered mail to the user’s mail server. The second is a host-based filter (where the filter is integrated into the hosting provider’s service directly) which can be called from the host’s MTA as part of mail reception or delivery.

Different groups of tests were performed for each software package depending on the features they offer. The EAI-readiness of each system component was defined in two levels: “Level 1” indicates partially EAI-ready as the email system can only send to and receive email from internationalized addresses; “Level 2” is fully EAI-ready, which means that in addition to Level 1 the email system also hosts or offers local internationalized addresses. More detailed information on the testing process can be found here.


The combined results of UASG030 and UASG030A are shown below.

Please note:

“Part” = Some tests passed; component has partial EAI support.

“Few” = Few tests passed; component does not have usable EAI support.

Overall, the results of UASG030A were very encouraging as all systems tested were able to offer some level of EAI support, with the majority offering Level 2 support. Further, the new spam filter tests showed positive results, as Spamassassin and Spamjadoo rose to the top with full Level 2 EAI-readiness. Mailchannels showed Level 1 support for its spam filtering proxy; however, it is actively working with the UASG on remediation efforts to become Level 2 ready.

Additionally, XgenPlus, Sendmail, and Halon passed most Level 2 EAI tests, while Thunderbird showed Level 1 support. Additionally, Dovecot, while not formally EAI-compliant, is still able to store and retrieve EAI mail using a workaround. This evaluation shows promising EAI support, but there is still more progress to be made.

Make Your Systems EAI-Ready

The UASG will continue to conduct EAI-readiness evaluations on an ongoing basis, as well as connect with the tested systems to discuss and support their efforts to become fully EAI-ready. Follow along with these efforts to achieve an #Internet4All on social media (Twitter, Facebook, LinkedIn). If you are looking to make your systems EAI-ready, please contact