From what I've read, you can update the Cydia to a newer, official version from within itself.
Sounds great.
Cydia has been updated with a iOS 7 look.
But it doesn't support iPhone 5s yet! Hope @saurik is working on that.
Cydia works on 64bit iPhones, just none of the packages do. The main package this is dependant on is Substrate, but I'm hardly going to blame saurik for taking a christmas break.