Quote:
26/04/2013 - mIRC v7.31
13.Added MONITOR protocol support for the notify list. mIRC will use
MONITOR automatically if it is listed in the 005 numeric.

Quote:
25/03/2016 - mIRC v7.44
39.Added check for servers that include MONITOR in numeric 005 but do
not actually support it. mIRC reverts back to ISON in this case.