While playing with the data format, I had a look at Africa/Luanda. It currently says: Zone Africa/Luanda 0:52:56 - LMT 1892 0:52:04 - AOT 1911 May 26 # Angola Time 1:00 - WAT Wikipedia has interesting details on this: http://en.wikipedia.org/wiki/Time_in_Portugal "By the Decree of 26 May 1911, a reform was approved regarding standard time in Portugal and in its overseas Empire" "These time zones were adopted on 1 January 1912." With the Portuguese law linked: http://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf I'd suggest that the data should be changed from 1911 May 26 to 1 January 1912, but I don't have much Portuguese language expertise to confirm this... The Africa file has no details on the 1892 change. Note that the Wikipedia page and law includes other countries as well. I send this because (a) currently it seems wrong and (b) it is evidence that some historic data can be found and should not be lost. Stephen