+ +C - Disable CTCP. All CTCP messages to the channel, except ACTION,
+ are disallowed.
+ ? +O - IRC Operator only channel.
+ ? +A - IRC server administrator only channel.
+ ? +T - No NOTICEs allowed in the channel.
+ ? +S - Only users connected via SSL/TLS may join the channel while this
+ mode is set. Users already in the channel are not affected.