Correct, it would be impossible for Khaled to block certain types of modifications (like hexing out the version and sneaky trojan-like changes) while still allowing for others (such as translations and skinning other compatability adjustments).
But the thing is, if I have enough know-how to turn mIRC into a trojan by modifying the binary code, they can also disable the integrity check. The only people who can't, are the people who just want to modify it for personal reasons.
