Although this is probably somewhat belated (and may have already been posted) I have determined that the newer versions of Palm Desktop work fine with older Plam OSs. I had a Zire 31 prior to getting the Kyocera 7135. In order to avoid any potential problems, I removed the 4.1.1 Desktop provided with the Zire 31 and installed the 4.1 Desktop provided with the Kyocera 7135. However, Desktop 4.1 is for Palm OS 4 devices and does not support some of the newer functions provided by OS 5. So, I reinstalled the 4.1.1 Desktop. I can now HotSync both the Kyocera 7135 and the Zire 31 with full Zire 31 functional capability for the new OS 5 functions such as Expense and Note Pad that are not on the Kyocera 31.