If a client requests extended room info according to XEP-128 (http://xmpp.org/extensions/xep-0128.html) Openfire's response contains malformed XML:

<field label="Number of occupants" var="muc#roominfo_occupants" >
<value>test</value>
<value>0</value>
</field>
<field/>

The bug can easily be fixed by commenting the whole line 1293:

/final FormField fieldOcc =/ dataForm.addField();
fieldSubj.setVariable("muc#roominfo_occupants");
fieldSubj.setLabel(LocaleUtils.getLocalizedString("muc.extended.info.occupants"));
fieldSubj.addValue(Integer.toString(room.getOccupantsCount()));