Dear list and GLAM-Wiki professionals and enthusiasts in particular, The Luxembourg Competency Network on Digital Cultural Heritage is developing a Shared Authority File, to combine the knowledge from national heritage institutions and to increase the impact of the member institutions' digitised collections. The Shared Authority File uses Wikibase as its main data store and internal user interface, and has created an extension that might be of relevance to the broader GLAM sector: A datatype for Extended Date Time Format compliant statements. Wikibase contains a datetime representation based on ISO 8601:2004 <https://en.wikipedia.org/wiki/ISO_8601>. The project extended the Wikibase software through an Extended Data Time Format extension, which includes ISO 8601:2019 <https://www.iso.org/obp/ui/#iso:std:iso:8601:-1:ed-1:v1:en>, and their extensions in a new datatype which can then be utilized within a Wikibase instance. This resulted in two open source products. A library <https://github.com/ProfessionalWiki/EDTF> for the validation and humanisation of EDTF dates in PHP, and an extension <https://github.com/ProfessionalWiki/WikibaseEdtf> to WikiBase to use this library. Both are available as open source software for all to use and improve. The humanisation is translated in various languages using Translate.wiki <https://translatewiki.net/wiki/FAQ>. With this email I’m asking support for the inclusion of this work into the fall release of the Wikibase Docker bundle. You can voice your support through this ticket: Include the EDTF Datatype extension in the Fall 2021 Wikibase Docker release <https://phabricator.wikimedia.org/T280656> This would allow other GLAM initiatives using Wikibase to easily make use of the EDTF standard within their own Wikibase deployments. Feedback and contributions to the repositories for this extension as a stand alone product are also welcomed! Thanks for your attention and best wishes, Maarten Brinkerink