--- a/browser/devtools/app-manager/content/index.js
+++ b/browser/devtools/app-manager/content/index.js
@@ -1,20 +1,21 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * 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/. */
 
-const Cu = Components.utils;
+const {utils: Cu, interfaces: Ci} = Components;
 Cu.import("resource:///modules/devtools/gDevTools.jsm");
 const {devtools} = Cu.import("resource://gre/modules/devtools/Loader.jsm", {});
 const {require} = devtools;
 const {ConnectionManager, Connection} = require("devtools/client/connection-manager");
 const promise = require("devtools/toolkit/deprecated-sync-thenables");
-const prefs = require('sdk/preferences/service');
-
+const prefs = require("sdk/preferences/service");
+const Services = require("Services");
+const Strings = Services.strings.createBundle("chrome://browser/locale/devtools/app-manager.properties");
 
 let UI = {
   _toolboxTabCursor: 0,
   _handledTargets: new Map(),
 
   connection: null,
 
   init: function() {
@@ -29,16 +30,17 @@ let UI = {
     window.addEventListener("message", this.onMessage);
   },
 
   onLoad: function() {
     window.removeEventListener("load", this.onLoad);
     let defaultPanel = prefs.get("devtools.appmanager.lastTab");
     let panelExists = !!document.querySelector("." + defaultPanel  + "-panel");
     this.selectTab(panelExists ? defaultPanel : "projects");
+    this.showDeprecationNotice();
   },
 
   onUnload: function() {
     for (let [target, toolbox] of this._handledTargets) {
       toolbox.destroy();
     }
 
     window.removeEventListener("unload", this.onUnload);
@@ -173,12 +175,38 @@ let UI = {
         this._handledTargets.set(target, toolbox);
         toolbox.once("destroyed", () => {
           this._handledTargets.delete(target)
         });
       });
     } else {
       return gDevTools.showToolbox(target, null, host);
     }
+  },
+
+  showDeprecationNotice: function() {
+    let message = Strings.GetStringFromName("index.deprecationNotice");
+
+    let buttons = [
+      {
+        label: Strings.GetStringFromName("index.launchWebIDE"),
+        callback: gDevToolsBrowser.openWebIDE
+      },
+      {
+        label: Strings.GetStringFromName("index.readMoreAboutWebIDE"),
+        callback: () => {
+          window.open("https://developer.mozilla.org/docs/Tools/WebIDE");
+        }
+      }
+    ];
+
+    let docShell = window.QueryInterface(Ci.nsIInterfaceRequestor)
+                   .getInterface(Ci.nsIWebNavigation)
+                   .QueryInterface(Ci.nsIDocShell);
+    let browser = docShell.chromeEventHandler;
+    let nbox = browser.ownerDocument.defaultView.gBrowser
+               .getNotificationBox(browser);
+    nbox.appendNotification(message, "app-manager-deprecation", null,
+                            nbox.PRIORITY_WARNING_LOW, buttons);
   }
-}
+};
 
 UI.init();

--- a/browser/locales/en-US/chrome/browser/devtools/app-manager.properties
+++ b/browser/locales/en-US/chrome/browser/devtools/app-manager.properties
@@ -1,12 +1,15 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # 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/.
 
+index.deprecationNotice=The App Manager will be removed in a future release.  Your projects have been migrated to WebIDE.
+index.launchWebIDE=Launch WebIDE
+index.readMoreAboutWebIDE=Read More
 # LOCALIZATION NOTE (device.deviceSize): %1$S is the device's width, %2$S is
 # the device's height, %3$S is the device's pixel density.
 # Example: 800x480 (86 DPI).
 device.deviceSize=Device size: %1$Sx%2$S (%3$S DPI)
 # LOCALIZATION NOTE (connection.connectedToDevice, connection.connectTo):
 # %1$S is the host name, %2$S is the port number.
 connection.connectedToDevice=Connected to %1$S
 connection.connectTo=Connect to %1$S:%2$S