As opposed to mediawiki, where all citation data are stored as strings, Wikidata has a strict typing system. https://www.wikidata.org/wiki/Special:ListDatatypes
- New wikibase format added and deployed
- isbns with dashes - deployed for all formats, see T230057
- Seperate properties for ISBN10 and ISBN13, deployed for wikibase format
- Identifiers key: added, see T245142
- pmcid without the pmc prefix - part done for all formats, see T157152
- Identifiers key: added and deployed for some identifiers, T245142
- Hierarchical structure for containers: T245142
- Plausibly a structured date format compatible with wikibase dates. However this isn't a priority because the wikibase api is pretty good at handling this on its own already ^-^.
- Validating language codes against wikibase's allowed values. see also T217258
- Plausibly including language code with every monolingual type, if possible. see also T217258
Alternatively we may even consider a wikidata format, which will actually try to obtain the correct QIDs in the background for certain params.