I had one of the original 500GB Time Capsules, and just yesterday, I got an alert from Software Update saying that an AEBS 5.5.1 update was out.
I did have my Time Capsule replaced last year under applecare as something went faulty, but Apple said it was a like for like replacement as they didn't make the 500gb models anymore..
Am i safe to install this update?!
Yes it is safe for you to update to version 5.5.1 of the Airport Utility. If your Time Capsule is a late 2009 model there will be an update for it, version 7.5.2. To update the Time Capsule or check for updates you need to open the Airport Utility. I have had no problems with either of the two updates and everything is working better then ever.