upgrading postfix from pt6.2 to postfix in pt7 won't work
until you issue a 'newaliases' command to update the format
of the hash tables.
also, if you do a rpm -e postfix, the preuninstall script should
stop the postfix deamon first, then proceed with the uninstallation...
Looking into it...
It's fixed; however, the new package won't build because of a problem with the glibc version currently in the (pre-7.1) build environments.
If you want to compile your own, the source RPM is attached to Bug #18976.
Fixed, now that we have gcc 2.96-62.