Time zone changes from version 2006c2 to 2006d1:
Date : Saturday April 22, 2006 16:00 CDT
File : 2006d1.txt

* Guatemala is applying DST, from 30.th. of April at 0:00
to 30.th. of September at 0:00. There are articles in
internet media that confirms this:
http://www.diariocolatino.com/internacionales/detalles.asp?NewsID=8079
http://www.mipunto.com/punto_noticias/noticia_latin.jsp?tipo=CENTROECO&archivo=060419183143.3zxeu5u5.txt
Also http://www.timeanddate.com/worldclock/city.html?n=94 shows it.
Thanks to Oscar van Vlijmen and Gwillim Law for this 
information!

* I just discovered 12 hours after the Sri Lanka change
from GMT+6 to GMT+5.5 was to take place (14.th. of April at 0:00)
that the change would not take place until 15.th. of April at 0:30

The page http://news.sinhalaya.com/wmview.php?ArtID=11002
claimed the following:

=== start of article ===
13 April 2006 - 07:38 
Change in Sri Lanka Standard Time 

Ministers have approved a Cabinet Memorandum submitted by Disaster 
Management and Human Rights Minister Mahinda Samarasinghe to revert 
the clock by 30 minutes from April 14 midnight.

With the implementation of this decision, the Sri Lanka Standard 
Time (SLST) reverts back to the zone GMT +5 1/2 hours, which was 
used prior to May 24, 1996 for over 50 years.

It is necessary to put the clock back by half an hour at 0030 hrs 
on April 15. This means 0030 hrs on April 15, 2006 (midnight of 
April 14, 2006 +30 minutes) at present, become 2400 hours of 
April 14, 2006 (midnight of April 14, 2006). 
=== end of article ===

Strange, I don't know what a GMT offset change has to do with
Disaster Management or Human Rights?

In the timezone.inf file of WTE 1.8 however there is no way to document 
GMT offset changes, the only possibility is to issue a whole new 
version of the file, so I decided not to issue a new file at that
moment, just to issue the old one back 12 hours later.
Instead in the coming Historic.txt file of WTE 2.0 it will be possible 
to put a GMT offset change at any moment in the past or future, so 
that only one new version of the file has to be issued. You can then 
check with Time Calculator any moment in time which GMT offset is 
(or was) used, and it will be correct.
The problem with WTE 1.8 is that it will show Sri Lanka to have 
GMT+5.5 all year of 2006, which is obviously not correct, in fact
it will show GMT+5.5 for Sri Lanka since 1800. With WTE 2.0 you
can get the whole transition history since 1800.

Regards, Jesper Nørgaard Welen

GMT = Greenwich Mean Time
DST = Daylight Saving Time
WTE = World Time Explorer

World Time Explorer 1.8:
http://www.worldtimeexplorer.com/index.html
e-mail: support@worldtimeexplorer.com
this text: http://www.worldtimeexplorer.com/2006d1.txt
... see also http://www.worldtimeexplorer.com/2006c2.txt

TZ Database:
http://www.twinsun.com/tz/tz-link.htm
ftp://elsie.nci.nih.gov/pub