they couldnt blame it on 6.21 because earlier versions wont work either ?

They could, they would be wrong, but they could.

If you let slip that you updated mIRC they will just say, oh well the new mIRC must have changed something in your own computer, and mIRC is a program we don't support, even going back to the old mIRC may leave the changed thing umm changed. Thanks for calling BT support. Is there anything else I can help you with?

btk(no correlation to bt, k?)