On Jan 14, 2011, at 1:00 PM, Ray Denenberg, Library of Congress wrote:

> From: Syd Bauman
>> Sent: Monday, January 10, 2011 5:04 PM
>> Subject: [DATETIME] comments on EDTF Specification DRAFT FOR REVIEW #2
>> even most of the authors of ISO 8601 consider it an egregious error to
>> permit "24:00" as a representation of midnight. The Library of Congress
>> specification should profile this use out. (And "23:59:60", and "23:60",
> There was a use case for this but I will need to dig through the archive to
> find it, and if so determine whether the person who proposed this still
> wants it and can satisfactorily explain the need for it.  If not, we can
> certainly drop it from the spec. 

On this topic, it may be worth mentioning that contrary to what I 
believe the EDTF spec says, the form "24:00:00" is defined and
legal in the relevant XSD datatypes; the lexical forms 
'2011-01-17T24:00:00' and '2011-01-18T00:00:00' have
the same value.

The seconds value '60', on the other hand, is not allowed in XSD
1.1; it was allowed in XSD 1.0, but only denoting a leap second.

I'm saying all this from memory; if chapter and verse are needed, I 
can provide them.

* C. M. Sperberg-McQueen, Black Mesa Technologies LLC