Which Processors can upgrade Software??

I have seen that some Rotels and others have software that can upgraded. Does anyone know of the models that can be upgraded and do you know if this has to be done by the factory or can it be done at home?? Does this mean it improves the coding, or can process the new formats.

Too individual to answer. Many brands permit upgraded firmware and do it in different ways from discs to internet/direct. Some may return to factory or dealer. Lots of different reasons for doing upgrades from fixing glitches to adding features.

My Anthem was simple to upgrade. I just downloaded a file, hooked up the cable (yeh, $20 at radio shack)) and connected the pre to my computer. Very simple. It really didn't make a difference either???
Rotel is done at home with a Zip file, it even comes with the cord, at Anthems prices they should have included them aswell.
Latest Denon Recievers have an ethernet port and upgrade over the web, this has allowed them to fix a number of HDMI issues. Plus they can be managed or controlled remotely over the web buy your installer/dealer.