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[DENICpublic-l] Thunderbird 45 Now Also IDNA-Compatible Due To DENIC Source Code Donation

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  • From: DENIC Presse <presse AT>
  • To: Public-l AT
  • Subject: [DENICpublic-l] Thunderbird 45 Now Also IDNA-Compatible Due To DENIC Source Code Donation
  • Date: Wed, 27 Apr 2016 09:25:49 +0200

Dear Sir or Madam,

DENIC has contributed part of the code for the new version 45 of the free e-mail client Mozilla Thunderbird (, which was launched in mid-April 2016: Thanks to this donation to the open-source community, Thunderbird now for the first time supports, besides numerous other novel functions, certain special characters (Internationalized Domain Names, IDNs) such as the German letter "Eszett" (ß) in e-mail addresses.

Up to now, if the domain part of an e-mail address (i.e. the part after the [at] sign) contained the letter "ß", this letter has been converted automatically to the character string "ss", despite mail programs having been able to handle this special character since August 2010 in theory. At that time, the Internet Standard for Internationalized Domain Names in Applications (IDNA2008) had been adapted correspondingly by the Internet Engineering Task Force (IETF).

DENIC, too, had included the "Eszett" more than five years ago in the set of characters permitted for .de domains already. However, to date the practicality of this had been limited due to the lack of support by web browsers and e-mail applications.

The DENIC-coded novelty in Thunderbird 45 is also of benefit to the users of other language families which are not based on Latin characters: In fact it paved the way for the entire range of characters under IDNA2008 to be fully available in Thunderbird starting as of now. Additionally, various characters from Greek, Farsi and Sinhala, for which re-routing has taken place so far, are now able to be resolved as characters in domains in their own right.

Overall, the IDNA2008 standard, which is based on the Unicode character set, allows the coding of thousands of new characters from various script systems. As a result, tens of thousands of characters from a multitude of different script systems may be used actively in Internet browsers and e-mail applications, provided that the required client support is available. On DENIC’s website, we provide a list of programs that are currently IDNA-capable (

Donated IDNA Source Code Earlier Implemented in Firefox 45 Already

Already since the start of March, the latest version of the Mozilla browser Firefox (Firefox 45) has been using the IDNA source code donated by DENIC ( and thus enables Internet users to access domains that contain certain special characters such as the German letter "Eszett" (ß). For the time being, the new code cannot yet be used in the Firefox application for Android. This is due to the particularities of the Google platform.

A very prompt reaction to the launch of the IDNA standard came at that time from the developers of the Libidn2 library, which serves to code and decode internationalized domain names: They implemented the revised algorithm of the IDNA standard on the basis of a corresponding source code donation by DENIC as early as in 2011.

Kind regards

Stefanie Welters
Public Relations

DENIC eG, Kaiserstraße 75 - 77, 60329 Frankfurt am Main, GERMANY
E-Mail: presse AT, Fon: +49 69 27235-274, Fax: -235

Angaben nach § 25a Absatz 1 GenG:
DENIC eG (Sitz: Frankfurt am Main)
Vorstand: Helga Krüger, Andreas Musielak, Carsten Schiefner, Dr. Jörg Schweiger
Vorsitzender des Aufsichtsrats: Thomas Keller
Eingetragen unter Nr. 770 im Genossenschaftsregister, Amtsgericht Frankfurt am Main

  • [DENICpublic-l] Thunderbird 45 Now Also IDNA-Compatible Due To DENIC Source Code Donation, DENIC Presse, 04/27/2016

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