According to the page that I got all of that information from ( http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/zone_tzid.html ) "South Africa Standard Time" is "Africa/Tripoli," and "Libya Standard Time" is not yet listed at all. But Tripoli _is_ in Libya, so I don't know. It looks like that page was last updated in March. However, given that Tripoli is the capital of Libya and that Windows now seems to have a "Libya Standard Time," it's likely correct. However, what's missing with your change is the change to `windowsTZNameToTZDatabaseName`. Its switch statement needs the conversion in the other direction, and it's actually that missing piece which is causing test failures for Dmitry on his Windows 8 box.