PDAs run special operating systems and software must be specifically compiled for them, so older versions of SwordSearcher will not work on PDAs or Smartphones.
The tools I use to develop SwordSearcher are Windows-only (WinXP/Vista, not Windows Mobile). A Smartphone version of SwordSearcher would be a ground-up new program. I still have a long wish-list and to-do list for SwordSearcher, so it is not likely that I will divide my development time between multiple platforms.
I did try this in the past, though. Because of limitations inherent to mobile devices, I would have had to take so much out of the user interface that the result would be SwordSearcher in name only. That kind of project does not really appeal to me.