When XMPP users join a MUC room, they often receive the last few messages that were sent to that room. The server tags those messages with a timestamp that's meant to be displayed by the client (instead of the current time). There's two XEPs for that tag: XEP-0091, and XEP-0203. Both provide exactly the same information, XEP-0203 just uses an updated timestamp format. Elsewhere in the code (e.g. in miranda/protocols/JabberG/jabber_thread.cpp), Miranda seems to support both XEPs, but in miranda/protocols/JabberG/jabber_groupchat.cpp, only XEP-0091 is supported.

Most servers still send both an XEP-0091 and an XEP-0203 tag, but I'd like to remove XEP-0091 support from ejabberd, as that has been obsoleted years ago (it's officially deprecated since 2007). I checked a few clients and so far Miranda's MUC code is the only place I could find that doesn't support XEP-0203 yet, so it would be wonderful if that could be added.