I promise that I've tried to figure this out on my own, but the threads here seem to get more and more full of esoteric iPhone jargon every time I come back!
It's simple though, so if someone wouldn't mind sparing me a few seconds...
I have a 1.1.1 fully unlocked Tmobile-simmed phone. I want the newest 1.1.3.
How do I get it? Is the "soft unlock" all that's available? Is there a guide I can follow?