I just downloaded and installed 7.1 and it does contain the new daylight savings time for U.S. Central time zone. To see if your installed version is ready, login in as root and run:
zdump -v /etc/localtime | grep 2007
(be sure and use the complete path to the localtime file)
My output results reflect the correct start and stop day/times.
/etc/localtime Sun Mar 11 07:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 CST isdst=0 gmtoff=-21600
/etc/localtime Sun Mar 11 08:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 CDT isdst=1 gmtoff=-18000
/etc/localtime Sun Nov 4 06:59:59 2007 UTC = Sun Nov 4 01:59:59 2007 CDT isdst=1 gmtoff=-18000
/etc/localtime Sun Nov 4 07:00:00 2007 UTC = Sun Nov 4 01:00:00 2007 CST isdst=0 gmtoff=-21600
HTH, Jim