Now that mIRC can represent $chr() values > 256 (Unicode codepoints) it would be a lot simpler and less confusing if those values could be represented in base-16, as this is the standard representation for Unicode codepoints (U+nnnn).
The following syntaxes would be beneficial to users:
//echo -a $chr(0x0E03)
//echo -a $chr(U+0E03)
The latter syntax being the standard Unicode codepoint notation. This would make it easier for users to copy paste these codepoints out of programs like charmap.exe and websites like these