Mcintosh C2200

Some selling a C2200 on Ebay claimed they sent the unit in for a new factory software upgrade. Anyone know what that uspgrade would be? Thanks!
Ask Mcintosh. I'm curious too.
I also would like to know.
I decided to call McIntosh and spoke with Ron. He nows nothing about any software upgrade for the C2200
The C2200 is microprocessor controlled. One of the features this allows is the ability to trim each input up or down by 6 dB. Due to and error in programing the micro some C2200s were shipped where the trim could only be adjusted down. If you have a C2200 that does not allow the trim to be set at a + value the preamp should have the micro changed. This is of course a warranty repair so contact your dealer or McIntosh service.
Folks: I checked with Mac just minutes ago. The only software changes were to fix a problem with the input trim. On some early production units, the gain would only go up, rather than up or down as it should. There have been no changes that would affect the sound of this excellent pre-amp.
Yes, spoke with Chuck at Mcintosh. He confirmed only the first 50 or so units Mcintosh made were affected.