I believe from the Cerience
forums that the only change is to make the viewer WM5 compatible. No other changes were made, or are planned at this point in time, which is a real shame, as Repligo only needs a few tweaks to be the perfect app for reading content that would normally be difficult to view on portable devices.
They haven't said so, but I think they're holding off with any improvements to put them into a version 3 so we can pay for the upgrade. Harsh, but probably true, if you read some of the posts on their forums (I'm Ommadawn there).
Repligo is still a great product though, and I'd recommend it for anyone to try out without hesitation.