Upgrades are now available for Viewsonic V35 and V37 Pocket PC devices here. Orders can be placed online or printed and sent in. There appears to be a free upgrade available for a limited time for devices recently purchased.
On the note of Viewsonic and the PPC devices, I need to use the opportunity to say how happy I am with the 802.11 SDIO wireless network card that I recnetly purchased. The card is amazingly small, easy to install, and works remarkably well. It performs way better that a similar compact flash card that I have for another device. If you're looking to network a V37 or similar device, this card is highly recommended.