This is done quite simply:

   1.Close (Exit) your mIRC client completely.
   2.Find in the root folder of the mIRC client (where you have it installed) a file with the name "mirc.ini" (make a copy for return).
   3.Open the original file "mirc.ini" in a text editor.
   4.Find the lines "[colors]" and "[palettes]".
   5.Edit under them lines below by adding new lines with color schemes to them. The main thing is to follow the sequence of line numbering "n0,n1,n2,n3...". Then save the update.
   6.Run the mIRC client and check the changes by clicking the "Colors" button on the top toolbar.
   7.You can now select new color schemes from the ones you added.


🅸🆁🅲 - 𝔦'𝔱𝔰 𝔸 𝕂𝖎ɴ𝙙 ᴏ𝙛 𝕄𝙖𝖌𝙞𝙘