Wikipedia's microformat-date emitting templates do not yet have a way to deal with dates in non-Gregorian calendars.

We do not claim to follow ISO 8601. Nonetheless as ISO 8601 requires mutual agreement among those exchanging information before using years outside the range 1583–9999 CE, the use of such templates for non-Gregorian dates, or dates outside that range might cause confusion.

Any editor encountering such usage should change the date to plain text with no date template; or if not confident in doing so, raise the matter on the relevant talk page.