IDN Implementation Guidelines

Norm
Norm title	IDN Implementation Guidelines
Type of norm	Guideline
Issuing body	ICANN
Geographic scope	Global
Status	Active
Official text	https://www.icann.org/en/system/files/files/idn-guidelines-22sep22-en.pdf
Language	English

The IDN Implementation Guidelines are a list of general standards for IDN registration policies and practices that are designed to minimize the risk of cybersquatting and consumer confusion, and respect the interests of local languages and character sets.

Registries seeking to deploy IDNs under their agreements with ICANN are authorized to do so on the basis of the Guidelines.

As of 2025, Version 4.1 is the most recent.

Versions

As of September 2025, there are the following versions:

Version 1.0

Version 1.0 was published on June 20, 2003, coinciding with the launch of deployment of IDNs under the IETF's Proposed Standard reflected in RFCs 3490, 3491, and 3492. These Guidelines were developed collaboratively by ICANN and leading IDN registries.

Version 2.0

Version 2.0 was published on November 7, 2005.

The IDN workshop during the Luxembourg meeting agreed that revision of the Guidelines was needed. Following this workshop, a Working Group of gTLD and ccTLD registries with IDN experience was formed to work on a revision of the guidelines, to be put forth for public comment. The Working Group formed was the IDN Guidelines Revision Working Group.

This second version of the Guidelines was necessary after experience was gathered in actual registry practice. Also, during the course of the review preceding this first revision, and as indicated in the comments received on the resulting draft, the initial version required extensive modification. The requisite changes could not readily be made by simple incremental changes to the initial text. However, given the urgent nature of some IDN concerns and the corresponding need for rapid response, the Working Group assigned to the task decided to produce a revised version of the Guidelines retaining their initial format as rapidly as possible, and then proceed with an alternate instrument with which to replace them altogether.

A draft Version 2 of the IDN Guidelines was published on September 20, 2005. A wide range of remarks and suggestions on the initial draft of Version 2 were submitted to a forum for public commentary that was open through October 23, 2005. On the basis of that material, a final draft Version 2 of the Guidelines was prepared and submitted to the ICANN Board for endorsement.

On November 8, 2005 the ICANN Board approved Version 2.0 for nine months only, asking the Working Group while further improvements were drafted. The Working Group was asked to return by the June 2006 meeting in Marrakesh with a "BCP-style" successor.

Version 2.1

Version 2.1 was published on February 22, 2006. After Version 2.0 had been in force for three months, the IDN Guidelines Revision Working Group issued a point-update to close a few gaps that implementers and security reviewers had flagged.

A revised Version 2.1 was published on February 27, 2006 with an ICANN announcement that reminded the community the Board had only granted Version 2.0 a nine-month lifespan and expected a more comprehensive successor by the June 2006 Marrakesh meeting. Because the rewrite took longer than expected, the Board later acknowledged Version 2.1 and extended its validity (Resolution 06.55 of June 30, 2006), accepting Working Group's request for additional time so that they would be able to continue its reframing of the guidelines in a manner appropriate for further development as a Best Current Practices (BCP) document, and to return to the board in time for the São Paulo meeting currently scheduled December 2-8, 2006.

Version 2.2

Version 2.2 was published on April 26, 2007. This revision had the purpose to make specific reference to IDN in top-level labels, and would be amended and supplemented in subsequent drafts in preparation for the release of top-level IDN labels in the production environment.

Version 3.0

Version 3.0 was published on September 2, 2011.. This new Version superseded version 2.2 to reflect the IDNABIS revision ("IDNA2008") of the initial IDNA protocol ("IDNA2003"). It was also prepared by the prepared by members of the IDN Guidelines Revision Working Group.

Version 4.0

Since publication of Version 3,0, there were changes in the terminology around IDNs and language tables, along with new technical considerations. Considering that, ICANN made a Call for Community Experts on July 20, 2015 to form a Working Group with the goal to review the IDN Implementation Guidelines. The IDN Guidelines Working Group (IDNGWG) was then formed in October 2015. The final proposed draft for Version 4.0 was announced on May 10, 2018 for consideration by the ICANN Board after several public community feedbacks.

Version 4.1

After the publication of the final draft of Version 4.0, subsequent discussions happened between the GNSO Council and the ICANN Board, resulting in the ICANN Board deferring implementation of guidelines 6a, 11, 12, 13, 18 in version 4.0 as they overlapped with ongoing work in the EPDP on Internationalized Domain Names. The ICANN Board then directed ICANN to publish the non-deferred guidelines in 4.0 as Version 4.1, which was published in September 22, 2022.

Internationalized Domain Name

Internationalized Domain Name

Internet Engineering Task Force

Request For Comments. Archival series dedicated to documenting Internet technical specifications, including general contributions from the Internet research and engineering community as well as standards documents (RFC Editor Model, Version 3).

Generic Top-level Domain

Country code top-level domain. Determined by "ISO 3166-1: Codes for the representation of names of countries and their subdivisions — Part 1: Country codes".

Generic Names Supporting Organization. Develops and recommends to the Board substantive policies relating to generic top-level domains and other responsibilities set forth in the Bylaws (ICANN Bylaws).