2.3a to 2.5 upgrade

I'm always the last to know. I'm running TivoDesktop 2.3a on my main computer. I upgraded my dsl router to the free BellSouth Versalink 327W wireless router 7 weeks ago. Nothing but problems since. After 30 hours and many calls to India and Manilla, BellSouth/ATT sent me a new router. That fixed some issues. There are still some and they are sending a tech out tomorrow. Tivo Transfer stopped working with the new router.
I checked for updates and as recent as a week ago Tivo Desktop said I had the current version. I just found this website as the main Tivo website seems to have been updated in the last week. Threads dated 8/8/07 now say 2.5 was released that far back: about the time mine stopped working.
No notices via email or the Tivo itself that there was an upgrade. I also have the plus addin.
I searched this entire site and there is no mention of what the upgrade is. how it works, what it solves, which version it is/is not compatible with, how to install it, will it damage any saved videos I have, etc.
Anyone have a clue? I also searched the Tivo site and found one page on 2.5 but zero real info. Very poor release since I've now spend 50 hours thinking the router is the issue when it probably isn't.
Tivo talks wirelessly to internet to get program info. My computer talks to internet. Tivo Desktop client will not talk to the Tivo unit. I can no longer see what programs are available for xfer nor can I do any xfers or conversions.
Again, can anyone please point me in the right direction?
Many Thanks.