Though the way it specifies raw UTC times is odd (8601 uses Z, 3339 uses -00:00), that got changed with RFC 9557 to align with 8601.
It also supports “zoned date times”, where instead of just using the UTC offset, you can also include a timezone identifier, e.g. 2020-01-01T00:00+01:00[Europe/Paris]. Useful if you’re doing calculations on dates but can be ignored otherwise.
Though the way it specifies raw UTC times is odd (8601 uses
Z, 3339 uses-00:00), that got changed with RFC 9557 to align with 8601.It also supports “zoned date times”, where instead of just using the UTC offset, you can also include a timezone identifier, e.g.
2020-01-01T00:00+01:00[Europe/Paris]. Useful if you’re doing calculations on dates but can be ignored otherwise.