Extended Date Time Format for Wikibase

Extended Date Time Format for Wikibase

We are happy to announce the release of Wikibase EDTF, our latest Wikibase extension. As the name suggests, Wikibase EDTF adds support the EDTF standard to Wikibase.

EDTF stands for Extended Date Time Format. The EDTF standard adds new date formats to ISO 8601-2019 2, including support for intervals, sets, uncertainty, precision and seasons. It was published by the US Library of Congress in 2019, after joint creation of the standard with the wider bibliographic community.

The new Wikibase EDTF extension adds an EDTF datatype to Wikibase, which supports the full EDTF specification. In other words, you can now have a property with type “Extended Date Time Format”, and then have statements with values like “15XX-12-25” or “{2010,2015..2020}”. This allows you to express dates too complex for the native Wikibase date format (ISO 8601-2004).

Wikibase validates the input, ensuring only valid EDTF values are stored. Furthermore, the user interface shows a “humanized” version of the EDTF value, which makes the value easier to understand to those not familiar with EDTF.

Wikibase EDTF statements in the UI

We created Wikibase EDTF for the Luxembourg Ministry of Culture, who financed the work. Professional.wiki thanks the Ministry for funding the project. Special thanks also go to Maarten Zeinstra, Maarten Brinkerink, Lucien Wagener, Claude Dessouroux and Chaudry Abubakr for their contributions.

Wikibase EDTF is available as free open source software (GPL V2) that can be installed on any Wikibase 1.35 instance. It relies on a new PHP EDTF library we developed for the project, which is also open source. We welcome contributions to both the Wikibase EDTF extension and the EDTF library!

Download and Installation

View the installation instructions and documentation.


See also

You can commission the Wikibase Consultancy for Wikibase development. Our other Wikibase services include managed Wikibase hosting and Wikibase setup. Contact us for more information.

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1 Comment

  1. This is great! Close to perfect – except for some reason the standard doesn’t allow specifying time of day in intervals, which is kind of a requirement for describing online events and sales that start/finish at particular times [in specific UTC offsets] (e.g. in JSON-LD Event syntax).

    Still, this is pretty helpful for day events when I’d otherwise have to use a qualifier for end time (or some other adaptation), so as to not get mixed up with which start/end time matched the other – and I’m sure there’ll be plenty of uses for the approximate/uncertain dates as well. Thanks for all the work… and to the Luxembourg Ministry of Culture for funding it, for the benefit of all!

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