Thank you for your bug report. I have not been able to reproduce this issue so far. I connected to several IRC networks and joined more than fifteen channels on all of them and the channels and channel count were displayed correctly. mIRC has no limit on the number of channels that you can join. However, some IRC networks do place a limit on the number of channels you can join and will prevent you from joining more than that limit. Are you sure that this is not the reason for the fifteen channel limit you are seeing?