I had the same issues.... Bought an ISY-99i IR/PRO years back, but never could get the IR working. Just gave up on that project. I somehow missed the 994i upgrade window, but wasn't overly concerned because the ISY-99i has been working ok, but I recently purchased an Insteon door sensor and tried to add it to my system and the ISY-99i just replied that it couldn't tell what the device was. No way to ever upgrade the software now, so I guess I'm screwed.
I don't want to pay full price to buy an all new device and then find out a year from now that I'm going to have to buy an all new device to support Philips Hue or whatever shiny new IoE hits the market after the 994 gets replaced by the next product.