If you're referring to the default version reply from mIRC, then you can not remove or change this.
To my knowledge the default version reply is no longer in a DLL but is hard-coded in the executable.
If I'm misunderstanding you, and you're talking about changing the reply for a script (which I'm thinking is more likely each time I read your post), then you would have to look for a line that reads something like
Additionally, if this is a scripting matter, then it should've been posted in the Scripts and Pop-Ups forum
