KEP2: Modification of datetime type, introduction of 'tz' sub-tag (wiki revision 10645 of 2010-11-19)

Georg C. F. Greve greve at
Wed Dec 15 19:42:20 CET 2010

On Tuesday 14 December 2010 11.03:23 Hendrik Helwich wrote:
> Also i am not sure if i understand the 4th bullet point: 
> "All such timestamps MUST be calculated against *Standard Time*, NOT in 
> Daylight Saving Time (DST). "

This is to avoid ambiguity.

Because the UTC time is calculated from the local time before storing it, 
doing this against standard time or DST would yield different UTC results. 

As we do not store whether or not this has been calculated from standard or 
DST (and neither do I think we should) we need to fix the reference point.

Standard time seemed the obvious choice for a great variety of reasons, 
including the question what regions would otherwise be doing that only have 
standard time. 

Best regards,

Georg C. F. Greve
Chief Executive Officer

Kolab Systems AG
Zürich, Switzerland

e: greve at
t: +41 78 904 43 33

pgp: 86574ACA Georg C. F. Greve
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 308 bytes
Desc: This is a digitally signed message part.
URL: <>

More information about the format mailing list