The process for upgrading the timezone information in the Calendar Server repository is as follows:

1. Create a new directory, "$NEWDIR", for the Olson data and our conversion of it.
2. ​Download the latest Olson data.
3. Extract the archive to the new directory renaming the extracted directory to "tzdata".
4. Run ​the tzconvert tool from the 'server' branch of the PyCalendar directory that Calendar Server's ./run -s will check out for you: src/zonal/tzconvert.py --prodid "-//calendarserver.org//Zonal//EN" --root "$NEWDIR"
5. That will create a "$NEWDIR/zoneinfo" directory.
6. ditto "$NEWDIR/zoneinfo" "CalendarServer/twistedcaldav/zoneinfo" (there may be files to delete in the destination: TODO, update this step to use rsync --delete or similar)
7. CalendarServer/bin/calendarserver_manage_timezones --update
8. Update twistedcaldav/zoneinfo/version.txt with info about the Olson version used
9. svn commit the changes after review