I've never see a source for V1.03. I've been led to believe that V1.02 is the last released, at least for American machines. It can be obtained here, bottom of the page, along with update instructions. http://tascam.com/product/2488/downloads/
Hi Rick. I borrowed a friends tascam and he has v1.03. I emailed tascam and here is their response.....
"There may have been some later models that were shipped from the factory with 1.03 but latest update available is 1.02. If this version was essential to it's operation it would have been posted on the website just like 1.02 was."