You cannot restore a backup from a device that runs an older OS and is a different brand or model. This is because system files are different between brands, models and operating system versions. However, if you are just concerned with your PIM data (contacts, calendar, tasks, notes and email) then sync the old PDA to Outlook on the desktop. That way when you sync your new PDA, it can sync to desktop Outlook and all that data will be put on the new PDA.
-------------------- Lisa Gade Editor in Chief, MobileTechReview