Again, this is a non-issue if you keep your mirc up to date. mIRC hasn't had a known exploit since 6.11 which released in late 2003, making it almost 4 years old.
It should be noted that when 6.11 was released on October 10th, and subsequently exploited, Khaled released a patch within 3 days, bringing the fix by October 13th.
It should
also be noted
and stressed that a version number in your version reply is not what would get you in trouble in a situation like the days between October 10th to 13th. It actually doesn't even matter what your version reply is to anyone attempting an exploit in the end.
Since most exploits are not costly to the exploiter at all, anyone exploiting mIRC in that time period won't care much about the version number and will probably just attempt the exploit on every client with "mIRC" in the reply... heck, they may not even look for the mIRC reply. In fact, versioning a channel and then wittling down the list is in most cases probably more costly than just running the exploit on the entire channel.
The scenario for exploits in most cases is actually more like what I just described than what you proposed. I've been through all the major exploits for mIRC, and each time, the exploiter will blindly run his code on all clients in a channel. Your version reply would mean nothing.
But again, this is not relevant, because mIRC has had no exploits for 4 years now, so this "issue" of yours really hasn't been a threat for a while, even if you say that a CTCP version will pre-empt an attack.
If mIRC all of a sudden becomes dangerous from version to version, then maybe this might be something to consider.. until then, your reasoning sounds shallow, and I'm pretty sure you have ulterior motives for custom replies... one's that have nothing to do with the "security"
FUD you just described.
