B&K Components Reference 30 vs 31

I use daily to own a B&K Reference 30 that I sold during one of my "too much stuff" equipment purges. A pity, because I really liked that pre/processor. That one showed a Firmware of 2.11, which I think was the last of that series. Now I've come across what the seller is claiming is the "Upgraded" Model 31. That one carries a 2.03 Firmware. I find next to nothing on the 31, and how it differs from the 30, and have no way of gauging whether this a an improvement or a downgrade compared to what I used to own. (Some AudioReview postings suggest 30s with early Firmware had issues with switching inputs, for example, and I find reviews of the later 50 series are less glowing than those of the 30.) 

Can anyone shed light on these units? The B&K that made them are no more, so no guidance is available from that front. Thanks.