diff --git a/src/ScalarMessaging.js b/src/ScalarMessaging.js
index 7ec928f895..fa7b8c5b76 100644
--- a/src/ScalarMessaging.js
+++ b/src/ScalarMessaging.js
@@ -480,7 +480,7 @@ function getMembershipCount(event, roomId) {
         sendError(event, _t('This room is not recognised.'));
         return;
     }
-    const count = room.getJoinedMembers().length;
+    const count = room.getJoinedMemberCount();
     sendResponse(event, count);
 }
 
diff --git a/src/VectorConferenceHandler.js b/src/VectorConferenceHandler.js
index 9ba46b2ab6..c53a01d464 100644
--- a/src/VectorConferenceHandler.js
+++ b/src/VectorConferenceHandler.js
@@ -72,7 +72,7 @@ ConferenceCall.prototype._getConferenceUserRoom = function() {
     for (var i = 0; i < rooms.length; i++) {
         var confUser = rooms[i].getMember(this.confUserId);
         if (confUser && confUser.membership === "join" &&
-                rooms[i].getJoinedMembers().length === 2) {
+                rooms[i].getJoinedMemberCount() === 2) {
             confRoom = rooms[i];
             break;
         }
diff --git a/src/components/structures/RightPanel.js b/src/components/structures/RightPanel.js
index 18523ceb59..bd4ed722cb 100644
--- a/src/components/structures/RightPanel.js
+++ b/src/components/structures/RightPanel.js
@@ -280,7 +280,7 @@ module.exports = React.createClass({
             const room = cli.getRoom(this.props.roomId);
             let isUserInRoom;
             if (room) {
-                const numMembers = room.getJoinedMembers().length;
+                const numMembers = room.getJoinedMemberCount();
                 membersTitle = _t('%(count)s Members', { count: numMembers });
                 membersBadge = <div title={membersTitle}>{ formatCount(numMembers) }</div>;
                 isUserInRoom = room.hasMembershipState(this.context.matrixClient.credentials.userId, 'join');
diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index 84b8788297..7b7a7bb813 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -363,7 +363,7 @@ module.exports = React.createClass({
         // XXX: EVIL HACK to autofocus inviting on empty rooms.
         // We use the setTimeout to avoid racing with focus_composer.
         if (this.state.room &&
-            this.state.room.getJoinedMembers().length == 1 &&
+            this.state.room.getJoinedMemberCount() == 1 &&
             this.state.room.getLiveTimeline() &&
             this.state.room.getLiveTimeline().getEvents() &&
             this.state.room.getLiveTimeline().getEvents().length <= 6) {