Yes, as ipsi says we're still fixing bugs and even adding some minor new features in 2.0.1, and we'll keep issuing bug fixes for it as we find / hear about bugs, but as far as big new features or a major overhaul that might make a dramatic difference in usability, that just isn't likely to happen at this point.
We already lost a colossal amount of time / money just getting 2.0 working on Palm OS - if it weren't for that I think we'd have had an iPhone version out before the end of '08 - and we pressed on and finished 2.0 in spite of that for the sake of our existing customers, but given how hard it was to get to even that point, and given that Palm has now completely killed Palm OS by replacing it with the non-backward-compatible webOS, it just doesn't make sense for us to make any more significant investments in Palm OS development.
If webOS were thoroughly / out-of-the-box backwards-compatible with old Palm OS applications, that might have been enough to get us to continue Palm development through 2.1, but it isn't (or at least they're saying it isn't), and frankly there are a lot of cool things we'd really like to do even in 2.1 that would be very difficult to do as long as we were continuing to support Palm OS, so the sooner we can shift the Palm OS version over to bug-fix-only mode, the better off we'll be. Which makes it very unlikely that even 2.1 will appear on Palm.
But we don't plan to drop Palm OS support until the iPhone / iPod Touch version is out in a full / feature-complete / yes-your-flashcards-will-work way, so there should never be a point at which you're stuck with Windows Mobile and nothing else if you want the latest version of Pleco.
