There are no plans to create a non-Windows version of mIRC. This includes Linux, MacOS, <your favorite non-Windows operating system here>. See:

To quote Khaled's personal FAQ page:

Question: Will you be making a version of mIRC for other operating systems?
Answer: I would love to create a cross-platform version of mIRC one day, however maintaining the Windows version takes up so much of my time that it is not currently practical.

Please don't request this anymore.