Data from bug 426610, quot vide, which is against RHEL:
Description of problem:
Argentina is going to use Daylight Saving Time (DST) on December 30, 2007
Official announcement (spanish)
Time zone changes and daylight saving time start/end dates
Clock changes in Buenos Aires
The change is already in <ftp://elsie.nci.nih.gov/pub/tzdata2007k.tar.gz>.
This probably should considered a security thing, too...
*** Bug 427256 has been marked as a duplicate of this bug. ***
Updated packages have been built for Rawhide, F 8 and F 7. Non-rawhide packages
are pending for push and should be available shortly.
tzdata-2007k-1.fc8 has been pushed to the Fedora 8 stable repository. If problems still persist, please make note of it in this bug report.