I can't answer your specific question. I have used some Technidol which I'm sure was at least 5-10 years post-purchase. It seemed to work fine. I'd try the 19-year-old stuff on a test roll before assuming anything.
I was in B&H Photo in NY about a week ago. They had plenty of Technidol. I have also seen websites of European merchants which show Technidol sold in small bottles. Technical Pan is discontinued but there seems to be plenty of Technidol around. It seems that it is easier to make photo chemicals in relatively small quantities than to make film that way.
Just as an aside, Technidol is a low contrast developer and can be used to produce pictorial contrast negatives from other brands of high contrast copy film or microfilms. That could explain why the stuff is still sold. Sure it's more expensive than the more commonly available developers here in the US, but it's cheaper than some of the other brands of specialty developers I've seen too.
If the packets have been stored well, the powder may still be in good condition. Sorry, but I haven`t seen this product for years and I have long forgotten what the instructions were.