It is not a problem if you use Unicode instead of code pages. If you don't use Unicode, then you won't be able to upgrade mIRC beyond 6.35 unless you want to try the somewhat troublesome methods of scripting code page support. Khaled has stated that there aren't any plans to provide code page support in mIRC anymore. After Unicode being available for a very long time, it's time for people to start making use of it. It's much superior to code pages.
How are people supposed to make use of it if it's only supported by 2 out of 3 users (wild guess)? You need to fall back to code pages or else NO one will migrate away... no one will upgrade because it's the only way to be sure you you can still communicate with people who don't support it yet. And people will just end up refusing to upgrade at all if it means they can't communicate anymore.
