diff --git a/chat/protocols/xmpp/xmpp-xml.jsm b/chat/protocols/xmpp/xmpp-xml.jsm
index 464f4d13d5..30997db5c9 100644
--- a/chat/protocols/xmpp/xmpp-xml.jsm
+++ b/chat/protocols/xmpp/xmpp-xml.jsm
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-this.EXPORTED_SYMBOLS = ["Stanza", "XMPPParser"];
+this.EXPORTED_SYMBOLS = ["Stanza", "XMPPParser", "SupportedFeatures"];
 
 var {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
 
@@ -47,6 +47,7 @@ var NS = {
   muc_user                  : "http://jabber.org/protocol/muc#user",
   muc_owner                 : "http://jabber.org/protocol/muc#owner",
   muc_admin                 : "http://jabber.org/protocol/muc#admin",
+  muc_rooms                 : "http://jabber.org/protocol/muc#rooms",
   conference                : "jabber:x:conference",
   muc                       : "http://jabber.org/protocol/muc",
   register                  : "jabber:iq:register",
@@ -91,6 +92,19 @@ var TOP_LEVEL_ELEMENTS = {
   "error"               : "urn:ietf:params:xml:ns:xmpp-streams"
 };
 
+// Features that we support in XMPP.
+// Don't forget to add your new features here.
+var SupportedFeatures = [
+  NS.chatstates,
+  NS.conference,
+  NS.disco_info,
+  NS.last,
+  NS.muc,
+  NS.ping,
+  NS.vcard,
+  NS.version
+];
+
 /* Stanza Builder */
 var Stanza = {
   NS: NS,
diff --git a/chat/protocols/xmpp/xmpp.jsm b/chat/protocols/xmpp/xmpp.jsm
index 8a85c710d7..a8185d7045 100644
--- a/chat/protocols/xmpp/xmpp.jsm
+++ b/chat/protocols/xmpp/xmpp.jsm
@@ -1703,6 +1703,27 @@ var XMPPAccountPrototype = {
         this.sendStanza(Stanza.iq("result", id, from, versionQuery));
         return;
       }
+      if (query && query.uri == Stanza.NS.disco_info) {
+        // XEP-0030: Service Discovery.
+        let children = [];
+        if (aStanza.attributes["node"] == Stanza.NS.muc_rooms) {
+          // XEP-0045 (6.7): Room query.
+          // TODO: Currently, we return an empty <query/> element, but we
+          // should return non-private rooms.
+        }
+        else {
+          children = SupportedFeatures.map(feature =>
+            Stanza.node("feature", null, {var: feature})
+          );
+          children.unshift(Stanza.node("identity", null,
+                                       {category: "client", type: "pc",
+                                        name: Services.appinfo.name}));
+        }
+        let discoveryQuery =
+          Stanza.node("query", Stanza.NS.disco_info, null, children);
+        this.sendStanza(Stanza.iq("result", id, from, discoveryQuery));
+        return;
+      }
     }
     this.WARN(`Unhandled IQ ${type} stanza.`);
   },