0004. We will use ISO-8601 for dates

Date: 2025-01-07

Status

Accepted

Context

We need to document the date format in use. We need to avoid confusion over DD-MM-YYYY and MM-DD-YYYY conventions as used in different countries, and we need to make obvious what the date format is.

Decision

We will use the ISO-8601 standard to represent dates in decision documents. The format is specified in https://www.iso.org/iso-8601-date-and-time-format.html and boils down to YYYY-MM-DD.

Consequences

Locale-specific conventions will not be respected if they contravene the ISO standard, and most locales do. The ISO-8601 format however is meant to be understood internationally.