Index: binaries/data/mods/public/gui/gamesetup/gamesetup.js
===================================================================
--- binaries/data/mods/public/gui/gamesetup/gamesetup.js
+++ binaries/data/mods/public/gui/gamesetup/gamesetup.js
@@ -1008,8 +1008,12 @@
 	},
 	"lobbyButton": {
 		"onPress": () => function() {
-			if (Engine.HasXmppClient())
-				Engine.PushGuiPage("page_lobby.xml", { "dialog": true });
+			if (!Engine.HasXmppClient())
+				return;
+
+			setLobbyButtonIcon(false);
+			g_LobbyDialogOpened = true;
+			Engine.PushGuiPage("page_lobby.xml", { "dialog": true, "callback": "setLobbyDialogClosed" });
 		},
 		"hidden": () => !Engine.HasXmppClient()
 	},
@@ -1087,6 +1091,10 @@
 	g_ServerPort = attribs.serverPort;
 	g_StunEndpoint = attribs.stunEndpoint;
 
+	setLobbyButtonIcon(false);
+	if (Engine.HasXmppClient())
+		g_UpdateLobbyNotification = setLobbyButtonIcon;
+
 	if (!g_IsNetworked)
 		g_PlayerAssignments = {
 			"local": {
@@ -1108,6 +1116,19 @@
 	setTimeout(displayGamestateNotifications, 1000);
 }
 
+function setLobbyButtonIcon(notify)
+{
+	Engine.GetGUIObjectByName("lobbyButton").sprite = notify ? "iconBubbleWhite" : "iconBubbleGold";
+
+	Engine.GetGUIObjectByName("lobbyButton").tooltip =
+		sprintf(translate("Show the multiplayer lobby in a dialog window. %(notification)s"), {
+			"notification": notify ? translate("(You have new lobby notifications.)") : ""
+	});
+
+	if (notify)
+		Engine.GetGUIObjectByName("onscreenToolTip").caption = translate("You have new lobby notifications. (Click the lobby icon button.)");
+}
+
 function initDefaults()
 {
 	// Remove gaia from both arrays
@@ -1910,8 +1931,12 @@
 		++g_LoadingState;
 	}
 	else if (g_LoadingState == 2)
+	{
 		handleNetMessages();
 
+		handleNetLobbyMessagesInBackground();
+	}
+
 	updateTimers();
 
 	let now = Date.now();
Index: binaries/data/mods/public/gui/gamesetup/gamesetup.xml
===================================================================
--- binaries/data/mods/public/gui/gamesetup/gamesetup.xml
+++ binaries/data/mods/public/gui/gamesetup/gamesetup.xml
@@ -4,6 +4,7 @@
 
 	<script directory="gui/common/"/>
 	<script directory="gui/gamesetup/"/>
+	<script file="gui/lobby/lobby_notifications.js"/>
 
 	<!-- Add a translucent black background to fade out the menu page -->
 	<object type="image" style="ModernWindow" size="0 0 100% 100%">
@@ -198,7 +199,6 @@
 			<object name="lobbyButton"
 				type="button"
 				style="IconButton"
-				sprite="iconBubbleGold"
 				sprite_over="iconBubbleWhite"
 				size="100%-41 346 100%-25 362"
 				hotkey="lobby"
Index: binaries/data/mods/public/gui/lobby/lobby.js
===================================================================
--- binaries/data/mods/public/gui/lobby/lobby.js
+++ binaries/data/mods/public/gui/lobby/lobby.js
@@ -126,6 +126,8 @@
  */
 var g_AskedReconnect = false;
 
+var g_CallbackSet = false;
+
 /**
  * Processing of notifications sent by XmppClient.cpp.
  *
@@ -394,9 +396,9 @@
  *
  * @param {Object} attribs
  */
-function init(attribs)
+function init(attribs = {})
 {
-	g_Dialog = attribs && attribs.dialog;
+	g_Dialog = !!attribs.dialog;
 
 	if (!g_Settings)
 	{
@@ -404,6 +406,8 @@
 		return;
 	}
 
+	g_CallbackSet = !!attribs.callback;
+
 	initMusic();
 	global.music.setState(global.music.states.MENU);
 
@@ -514,7 +518,11 @@
 	if (g_Dialog)
 	{
 		Engine.LobbySetPlayerPresence("playing");
-		Engine.PopGuiPage();
+
+		if (g_CallbackSet)
+			Engine.PopGuiPageCB();
+		else
+			Engine.PopGuiPage();
 	}
 	else
 	{
Index: binaries/data/mods/public/gui/lobby/lobby_notifications.js
===================================================================
--- binaries/data/mods/public/gui/lobby/lobby_notifications.js
+++ binaries/data/mods/public/gui/lobby/lobby_notifications.js
@@ -0,0 +1,49 @@
+
+/**
+ * Current lobby username. Cannot contain whitespace.
+ */
+const g_LobbyUsername = Engine.LobbyGetNick();
+
+/**
+ * Indicates if lobby dialog is opened.
+ */
+var g_LobbyDialogOpened = false;
+
+/**
+ * Function name for call when notification happens in lobby.
+ */
+var g_UpdateLobbyNotification = notify => {};
+
+/**
+ * Lobby net messages, that triggers a notification.
+ */
+var g_LobbyNetMessageTypeNotification = {
+	"system": {
+		"disconnected": msg => true
+	},
+	"chat": {
+		"subject": msg => true,
+		"role": msg => true,
+		"room-message": msg => msg.text.toLowerCase().indexOf(g_LobbyUsername.toLowerCase()) != -1,
+        "kicked": msg => msg.nick == g_LobbyUsername,
+        "banned": msg => msg.nick == g_LobbyUsername,
+        "private-message": msg => true
+	}
+};
+
+function handleNetLobbyMessagesInBackground()
+{
+    if (!g_LobbyDialogOpened)
+    {
+        let msg = Engine.LobbyGuiPollNewMessage(); // Only poll new messages no historic.
+        if (msg && g_LobbyNetMessageTypeNotification[msg.type] &&
+            g_LobbyNetMessageTypeNotification[msg.type][msg.level] &&
+            g_LobbyNetMessageTypeNotification[msg.type][msg.level](msg))
+            g_UpdateLobbyNotification(true);
+    }
+}
+
+function setLobbyDialogClosed()
+{
+	g_LobbyDialogOpened = false;
+}
Index: binaries/data/mods/public/gui/session/menu.js
===================================================================
--- binaries/data/mods/public/gui/session/menu.js
+++ binaries/data/mods/public/gui/session/menu.js
@@ -72,6 +72,21 @@
 	updateGameSpeedControl();
 	resizeDiplomacyDialog();
 	resizeTradeDialog();
+	g_UpdateLobbyNotification = setLobbyButtonIcon;
+}
+
+function setLobbyButtonIcon(notify)
+{
+	let menuButton = Engine.GetGUIObjectByName("menuButton");
+	let lobbyButton = Engine.GetGUIObjectByName("lobbyButton");
+
+	menuButton.caption = translate("Menu");
+	lobbyButton.caption = translate("Lobby");
+	if (notify)
+	{
+			menuButton.caption = menuButton.caption + "*";
+			lobbyButton.caption = lobbyButton.caption + "*";
+	}
 }
 
 function initMenuPosition()
@@ -127,7 +142,9 @@
 		return;
 
 	closeOpenDialogs();
-	Engine.PushGuiPage("page_lobby.xml", { "dialog": true });
+	setLobbyButtonIcon(false);
+	g_LobbyDialogOpened = true;
+	Engine.PushGuiPage("page_lobby.xml", { "dialog": true, "callback": "setLobbyDialogClosed" });
 }
 
 function chatMenuButton()
Index: binaries/data/mods/public/gui/session/session.js
===================================================================
--- binaries/data/mods/public/gui/session/session.js
+++ binaries/data/mods/public/gui/session/session.js
@@ -732,6 +732,8 @@
 
 	handleNetMessages();
 
+	handleNetLobbyMessagesInBackground();
+
 	updateCursorAndTooltip();
 
 	if (g_Selection.dirty)
Index: binaries/data/mods/public/gui/session/session.xml
===================================================================
--- binaries/data/mods/public/gui/session/session.xml
+++ binaries/data/mods/public/gui/session/session.xml
@@ -4,6 +4,7 @@
 
 <script directory="gui/common/"/>
 <script directory="gui/session/"/>
+<script file="gui/lobby/lobby_notifications.js"/>
 
 <object name="sn">