By the UASG Measurement Working Group

The Universal Acceptance Steering Group (UASG) completed a UA-readiness evaluation of the content management system (CMS) WordPress and 15 of its subscription, membership, and event management plugins. WordPress currently powers over 40% of all websites. Ensuring a leading CMS system, like WordPress, supports all Internet users equally helps provide a more inclusive and multilingual #Internet4All.

Specifically, WordPress and the selected plugins were tested to evaluate how well they support:

  • Internationalized Domain Names (IDNs) and Internationalized Resource Identifiers (IRIs) (e.g., 普遍接受-测试.世界 or UniversallyAccepted-Tested.World in Chinese),
  • Email Address Internationalization (EAI) (e.g., อรุณสวัสดิ์@ดาต้าเมล.ไทย or Goodmorning@Datamail.Thai in Thai)

Overall, the evaluation found strong support for IRI paths and IDNs, but low support for EAI. This means IDNs will function correctly when registered with a WordPress-based site, as well as properly display and hyperlink in newsletters or on event pages, etc. However, when it comes to EAI, users may have difficulty using their internationalized email address of choice to register for an event, subscribe for a newsletter, send and receive emails, etc.

Additional details on the evaluation are below and the full test results are available, here (UASG032).

What we tested:

In addition to WordPress, the plugins tested include:

How we scored:

To be UA-ready, an Internet-enabled application or system must accept, validate, store, process, and display UA identifiers, as explained in detail in the Universal Acceptance Readiness Framework (UASG026). For this evaluation, each plugin received three separate scores ranging from A-D indicating whether it passed or failed to support the test internationalized domain names, internationalized email addresses, and IRI path variations.

UA-Readiness Level Description
Y A-Level All accept, validate, store, process, and display tests were passed.
B-Level The application supports IDN/EAI, but at least one aspect of testing failed.
N C-Level The application’s frontend system shows IDN/EAI support, but deeper architecture reforms are needed to properly validate, store, process, and/or display the UA identifier.
D-Level No tests were passed.


WordPress and a majority of the plugins received passing scores for their support of IDNs (11 B-Level, 5 C-Level) and IRI paths (10 A-Level, 2 B-Level, 4 C-Level). The plugins that rose to the top with passing scores included:

  • Subscription management: OptinMonster, Newsletter.
  • Membership Management: MemberPress, WooCommerce, Restrict Content Pro, Paid Memberships Pro.
  • Event Management: Events Manager, Event Organiser, All-in-One, Event Calendar, Event Espresso 4 Decaf.

However, all the tested systems received a failing C-Level score for EAI support. The email evaluation consisted of six email address categories that tested for support of various characters and coding standards, including combinations of domain names in ASCII and IDN (in A-label or U-label), as well as mailbox names in ASCII and Unicode. The results indicate moderate levels of support for email addresses that use IDNs when ASCII is used in the mailbox name (i.e., ascii@idn.idn), but all tests failed to support email addresses using Unicode in the mailbox name (i.e., unicode@idn.idn).

More information on the testing methodology and detailed results and charts can be found, here.

While it is encouraging to see a major CMS system like WordPress and associated plugins support IDNs, there is more work to be done to ensure all users can navigate the Internet using an email address in their language and script of choice. After conducting these evaluations, the UASG reached out to the plugins tested regarding their IDN and EAI support and will continue to offer guidance and resources to help update their systems to be fully UA-ready.

For more information about the UASG and ways you can get involved, visit, and follow, like, and share with the UASG on social media (TwitterFacebookLinkedIn).

Additionally, on 3 June at 13:00 UTC, there will be an opportunity to learn about the current work being done by the UASG to achieve an #Internet4All during ICANN71 Prep Week. Stay tuned on UASG social channels for more information.