Yes, a new version of the agent was released this week as reported in the Member News forum (http://www.worldcommunitygrid.org/forums/wcg/viewthread?thread=930).

This is normal behavior for software firewalls. They normally generate a cryptographic hash for each executable allowed to pass through. A new version of the agent was released and didn't match what you had previously allowed. Thus it doesn't know if it's a valid upgrade or if a virus had infected it or replaced it. That's why your firewall is asking for your permission to allow it though. This will happen anytime the agent or any other software that accesses the internet is upgraded. e.g. I have to reauthorized Mozilla everytime I upgrade it.