Thanks Tony, problems might arise where your anti virus stops you from running because it has not been updated for a long while. What AV are you using? I am running the latest Norton, my iPhone/iPad AV warns me when update of IOS is available - doesn't stop me continuing to use old IOS though, at least for couple of days.
I use Kaspersky Internet Security and Super Anti-spyware Professional. They both update automatically. I just have to be sure to run them before a race so they don't update during an event.