include the 'a' format token in your WHOX token request. When you get
a reply, do appropriate caching.
-3) When new users join a channel that your client does not know the accountname
+3) If the extended-join capability is available, enable it at client capability
+ negotiation time during the login handshake, and then set the accountname
+ based on what is sent in the extended JOIN command.
+
+ Otherwise, if extended-join is unavailable:
+ When new users join a channel that your client does not know the accountname
for yet, do a WHO query against that client, again including the 'a' format
token in your WHOX token request field. When you get a reply, do appropriate
caching.