Note: This instruction is out of date.  We need to update the tooling/instruction for 1.9 and beyond - 2010-03-03 Yoshito Umaoka

Do the following to update to a new timezone database.

1. Download the latest version of the data from ftp://elsie.nci.nih.gov/pub/
   • The file you care about will look like tzdata2007g.tar.gz (with perhaps different year/letter)
   • Unpack, and copy contents into {cldrdata}\tools\java\org\unicode\cldr\util\data
   • Edit the file {cldrdata}\tools\java\org\unicode\cldr\util\data\tzdb-version.txt to change the version, eg for the file tzdata2007a.tar.gz, the version is 2007a.
   • If you are using Eclipse, remember to refresh the project.
2. Diff zone.tab with CVS.
   • if any IDs in zone.tab changed name, add the mapping to org.unicode.cldr.util.ZoneParser.FIX_UNSTABLE_TZID_DATA
   • The format is <new name>, <old name>
     • Eg {"America/Argentina/Buenos_Aires", "America/Buenos_Aires"},
3. Now Verify
   • Run CountItems -Dmethod=genSupplementalZoneData to generate new data.
   • Paste the <zoneFormatting> ... </zoneFormatting> into supplementalData.xml
   • Paste the <variable id="$tzid" type="choice"> ... </variable>  into supplementalMetadata.xml
   • It also creates a file prettyPathZone.txt. Copy that to util/data/
   • Produce Diffs in CVS for all three files files.
   • CAREFULLY COMPARE THE RESULTS TO THE LAST VERSION FOR BOTH
   • In supplementalData.xml, any changed name from zone.tab must show a diff like:
     • old: <zoneItem type="Atlantic/Faeroe" territory="FO"/>
     • new: <zoneItem type="Atlantic/Faeroe" territory="FO" aliases="Atlantic/Faroe"/>
   • That is, the old name must not change, just add new aliases.
   • In both files, any new zone.tab ID must show up, eg.
     • supplementalData.xml, new: <zoneItem type="Australia/Eucla" territory="AU"/>
     • supplementalMetadata.xml, new: Australia/Eucla
4. REMOVE IDs. This doesn't happen very often, but requires some real thought when it does.
   • If there are any $tzid's that are in the last version that are not in the current,
   • find out what "real" alias it should point to. There are 2 types.
   • 1. ID was removed completely, like HST. In that case, there will be no item or alias in zoneItem's.
     • Look at the old supplemental data to determine what it used to map to (eg Pacific/Honolulu)
     • Add to supplementalMetaData
     • <zoneAlias type="HST" replacement="Pacific/Honolulu"/>
     • Add ZoneParser.ADD_ZONE_ALIASES_DATA
     • eg {"HST", "Pacific/Honolulu"},
     • Rerun CountItems.genSupplementalZoneData()
   • 2. ID is no longer in zone.tab (after fixing "A"), but is still linked.
     • In that case, there will still be a zoneItem as an alias, eg
       • <zoneItem type="Africa/Bamako" territory="ML" aliases="Africa/Timbuktu"/>
     • Add to supplementalMetadata. Use the zoneItem info
       • <zoneAlias type="Africa/Timbuktu" replacement="Pacific/Honolulu"/>
     • Add to CountItems.FIX_DEPRECATED_ZONE_DATA. Example:
       • "Africa/Timbuktu",
     • Rerun CountItems.genSupplementalZoneData()
     • Sometimes the aliases will be on the wrong element. If so, add to org.unicode.cldr.util.ZoneParser.PREFERRED_BASES.
5. Repeat C and D until no changes occur.
   • When you are all done, there should ONLY be additions to $tzid and zoneItem's.
6. For any of the timezones that are added, changed, or deleted, you will need to make the appropriate metazone updates to supplemental/metazoneInfo.xml.  For each zone, you will need to read the Olson TZ data file ( they are grouped by continent ), and compute the transition times ( in GMT, not local time ) for any metazone transitions.  A metazone transition usually occurs when the abbreviation changes, for example, from E%sT to C%sT.  If a zone is simply starting or stopping observence of DST, then usually no metazone transition is necessary.  Example, going from E%sT to EST is NOT a metazone transition.
7. Check in the new supplemental files and the data files in ...org\unicode\cldr\util\data
1. just the data files that are already checked in (eg check in 'africa', but not 'factory')
2. (Note: the code in CountItems and StandardCodes means that we have to duplicate a bit of process above, but for now it's not worth fixing.)
8. Do Regenerate Charts