Yes, but while they supported the old ones they'd have to release two copies of each OS, one for each key.
So either they'd drop the old one immediately (probably not) or they'd release two of each OS (possible, but I'm sure TI doesn't want to put their customers through figuring out which revision they have

)
We're probably safe.
Thanks for the explanation, graphmastur! I do wonder if we could find a better way...