Jun - you'll have to write custom export/import sripts I'm afraid.
If the sites you have are working reasonably well, and you don't expect a huge growth in users, you might just leave them alone. On the other hand, if you think you'll ever have to upgrade it, you're probably better off doing it ASAP.
Michael - for the most part I think packages are pretty stable. I don't expect much change at all (I think getting Neophytos's improvements to search are important, though). Folks at Jun's company have been working on doing some additional porting but I don't know if they'll get done in time for this release (I need to check with them soon, I guess).
