Updating Ports on Production Servers

[Lewis Watson]

I am a big fan of the ports collection and use the ports to build the
programs I use on our production servers. Now I am wanting to update some
ports and have a chicken and egg issue. If I go ahead and update a port
(pure-ftpd for example)...

After I run "CVSUP portfile"  the old version that's running has no
graceful way of being removed.  If I try to remove it I am notified that
the version that is running is not on the machine so then I guess force
the uninstall? Either that or just do a make - make install and overwrite
the old port binaries with the new binaries ( this does not seem good
either).

It appears the only way to cleanly upgrade a port is to deinstall the
current port. Run CVSUP portfile... and get the new port files... do a
make - make install and get the new version of the port installed. This
opens the machine to several minutes of downtime while the program is
being made... (not good either)

Please tell me the way that it's being handled on your servers/ network...
Thanks!
Lewis