You can find some limited support on the HP website: http://h10025.www1.hp.com/ewfrf/wc/p...&product=82118
This was the last Handheld PC produced by HP. The Jornada 728 was released in 2002. It runs on the Windows CE 3.0 based Handheld PC 2000 and contains a slightly higher OS revision than the 710 or 720, providing the user with native PPTP VPN functionality.
HP decided to come out with an updated version of their handheld PC/palmtop line in 2002, and the 728 is the result. It is basically the same thing as the 720 except with 64MB RAM, a slightly newer casing, and (presumably) updated drivers. However, the operating system is the same, as well as the Office and PIM applications.
HP is not going to offer an upgrade for this model. HP has not released an updated ROM and it is unlikely that they will. You might be able to get what you need from some of the ebay sellers of this product. It you email/contact them and ask, they may be willing to help. This is one ebay seller: