Unofficial Protocol Docs: MODEs - mono-chat/Mono-Project GitHub Wiki

Most of these modes are the same as that of a standard IRCd network.

Channel Modes:

b - "Ban" - Can be used to get a list of ban (ACCESS DENY) entries.
d - "Cloneable" - When the room fills up, a new room will be created with the same name, plus a number between 1 and 99. Cannot be set by normal users.
e - "Clone" - This room is a clone of a room that is set to mode +d. Cannot be set by normal users.
f - "Filter" - MSN's built-in profanity filter is being used. Can only be set during room creation.
g - "Special Guest" - Puts the MSN Chat control in to special guest chat mode. Used in OnStage. Cannot be set by normal users.
h - "Hidden" - Room is not shown on any sort of room listings. Same as +s, can't be used with +p or +s.
i - "Invite" - Room is set as invite only.
k - "Key" - Room has an entry password set. Same as PROP MEMBERKEY.
l - "Limit" - Room has a user limit set. Anything above 100 users must be set during room creation and may not actually be enforced.
m - "Moderated" - Users in the room can be "specced", or set mode -v, and they cannot speak.
n - "No External Messages" - Only people that are actually in the room, can speak in the room. If -n, you can talk in the room without actually being there.
p - "Private" - Room is not shown on the room listings, and you can only find out the amount of people in the room and the name. Cannot be used with +h or +s.
r - "Registered" - Official MSN room, shows as having a butterfly on the room list. Cannot be set by normal users.
s - "Secret" - Room is not shown on any sort of room listings. Same as +h, cannot be used with +h or +p.
S - "Subscriber" - Only subscribers to MSN Chat are allowed to speak in the room. Cannot be set by normal users.
t - "Only Hosts Set Topic" - Only a host, owner, or MSN official can change the room topic. If -t, any user can change the topic.
u - "Knock" - When someone can't get into the room for whatever reason, all hosts receive a message stating so, though the MSN Chat Control does not display the message.
w - "No Whispers" - Normal users cannot whisper non-hosts. Note that this is a lowercase w.
W - "No Guest Whispers" - Guests cannot whisper non-hosts. Note that this is an UPPERCASE W.
x - "Auditorium Mode" - Normal users cannot see each other in the room and can only see hosts, while hosts can see everyone. Cannot be set by normal users.

User Modes:

v - "Voice" - User can speak in a moderated (+m) room. The user is labeled a Participant.
o - "Host" - User is a host in the room (brown hammer).
q - "Owner" - User is an owner in the room (gold hammer).
p - "Profile" - Only used with MSN Chat 3.0, indicates the user has a profile.

Self Modes:

h - "Host" - Used to host/owner yourself in a room (MODE YourName +h Password)
i - "Invisible" - Your info cannot be seen unless a user is in the same room as you are
x - "IsIRCX" - Your connection is using IRCX mode. MSN Chat only allows IRCX connections. In mIRC, type //mode $me to make it appear.