They were talking about what certain hex codes meant in a 16C54 and that they were different for the 16C84 (now 16F84). Sorry I am dating myself!! I believe it was the second, maybe third set of hex codes or at least in the first line. The discussions lead to use of a hex code editor that could change individual characters to get the needed results.

I suppose one could compile a simple program and look at the results in the hex code to identify the difference. Not sure it is worth the trouble.