The 16C84 was replaced a LONG, LONG time ago by the 16F84, which in turn was replaced by the superior 16F628 - and even that was last century!.
There's very little difference between the three devices, and it's trivial to change from one to the other - there were migration documents from one to the other on the MicroChip website, but the 16F84 to 18F628 one was removed when the reintroduced the 16F84 - at a MUCH higher price, as people get asking for it. The 16C84 to 16F84 one may still be on their website?.