Sometimes things just work

Logged in to a customers ASA to do some VPN work and some horrible outside NATing. I noticed the software seemed kinda old, so..
ASA5505# sh ver
Cisco Adaptive Security Appliance Software Version 7.2(1)
Device Manager Version 5.2(1)
Compiled on Wed 31-May-06 14:45 by root
System image file is "disk0:/asa721-k8.bin"
Config file at boot was "startup-config"
ASA5505 up 3 years 175 days
It would be a shame to lose that uptime just to update the ios, right?