I don't know if this is caused by a bug or not, but perhaps we can figure out what's the problem here.
So I've been successfully using v7.29 with a client certificate (mIRC Options -> Connect -> Options -> SSL -> Private key file / Certificate chain file (.pem (key + certificate))).
Now I just tried the new mIRC beta v7.31 and noticed that my client certificate no longer works, it's as if I have none.
When I go back to v7.29, it works fine.
Has anyone tried this yet, and has gotten it to work or experienced the same problem?