diff --git a/package.json b/package.json
index 5b280bb33..d2a5a8edb 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,7 @@
     "tslint": "^4.4.2",
     "typedoc": "^0.5.10",
     "typedoc-plugin-external-module-name": "git://github.com/PanayotCankov/typedoc-plugin-external-module-name.git#with-js",
-    "typescript": "~2.2.1"
+    "typescript": "^2.4.1"
   },
   "scripts": {
     "setup": "npm run dev-link-tns-platform-declarations && npm run dev-link-tns-core-modules && npm run dev-link-tests && npm run dev-link-apps",
diff --git a/tests/app/TKUnit.ts b/tests/app/TKUnit.ts
index bbe2457a8..a8b14b2ba 100644
--- a/tests/app/TKUnit.ts
+++ b/tests/app/TKUnit.ts
@@ -214,7 +214,7 @@ export function assertNotEqual(actual: any, expected: any, message?: string) {
     }
 }
 
-export function assertEqual<T extends { equals?(arg: T): boolean }>(actual: T, expected: T, message: string = '') {
+export function assertEqual<T extends { equals?(arg: T): boolean } | any>(actual: T, expected: T, message: string = '') {
     if (!types.isNullOrUndefined(actual)
         && !types.isNullOrUndefined(expected)
         && types.getClass(actual) === types.getClass(expected)
diff --git a/tns-core-modules/application/application.android.ts b/tns-core-modules/application/application.android.ts
index ce0731f4f..5dd1f8433 100644
--- a/tns-core-modules/application/application.android.ts
+++ b/tns-core-modules/application/application.android.ts
@@ -1,6 +1,7 @@
 import {
     AndroidActivityBundleEventData, AndroidActivityEventData, ApplicationEventData, OrientationChangedEventData,
-    AndroidApplication as AndroidApplicationDefinition
+    AndroidApplication as AndroidApplicationDefinition,
+    AndroidActivityResultEventData, AndroidActivityBackPressedEventData, AndroidActivityRequestPermissionsEventData
 } from ".";
 
 import {
@@ -102,6 +103,19 @@ export class AndroidApplication extends Observable implements AndroidApplication
         }
     }
 }
+export interface AndroidApplication {
+    on(eventNames: string, callback: (data: AndroidActivityEventData) => void, thisArg?: any);
+    on(event: "activityCreated", callback: (args: AndroidActivityBundleEventData) => void, thisArg?: any);
+    on(event: "activityDestroyed", callback: (args: AndroidActivityEventData) => void, thisArg?: any);
+    on(event: "activityStarted", callback: (args: AndroidActivityEventData) => void, thisArg?: any);
+    on(event: "activityPaused", callback: (args: AndroidActivityEventData) => void, thisArg?: any);
+    on(event: "activityResumed", callback: (args: AndroidActivityEventData) => void, thisArg?: any);
+    on(event: "activityStopped", callback: (args: AndroidActivityEventData) => void, thisArg?: any);
+    on(event: "saveActivityState", callback: (args: AndroidActivityBundleEventData) => void, thisArg?: any);
+    on(event: "activityResult", callback: (args: AndroidActivityResultEventData) => void, thisArg?: any);
+    on(event: "activityBackPressed", callback: (args: AndroidActivityBackPressedEventData) => void, thisArg?: any);
+    on(event: "activityRequestPermissions", callback: (args: AndroidActivityRequestPermissionsEventData) => void, thisArg?: any);
+}
 
 const androidApp = new AndroidApplication();
 // use the exports object instead of 'export var' due to global namespace collision
diff --git a/tns-core-modules/data/observable-array/observable-array.ts b/tns-core-modules/data/observable-array/observable-array.ts
index ac2a16b93..6b3c28034 100644
--- a/tns-core-modules/data/observable-array/observable-array.ts
+++ b/tns-core-modules/data/observable-array/observable-array.ts
@@ -324,3 +324,7 @@ export class ObservableArray<T> extends observable.Observable implements observa
         return this._array.reduceRight(callbackfn, initialValue);
     }
 }
+export interface ObservableArray<T> {
+    on(eventNames: string, callback: (data: observable.EventData) => void, thisArg?: any);
+    on(event: "change", callback: (args: observableArrayDef.ChangedData<T>) => void, thisArg?: any);
+}
\ No newline at end of file
diff --git a/tns-core-modules/data/virtual-array/virtual-array.ts b/tns-core-modules/data/virtual-array/virtual-array.ts
index ab84307bf..67a4c8da0 100644
--- a/tns-core-modules/data/virtual-array/virtual-array.ts
+++ b/tns-core-modules/data/virtual-array/virtual-array.ts
@@ -1,4 +1,4 @@
-import { Observable } from "../observable";
+import { Observable, EventData } from "../observable";
 import * as virtualArrayDef from ".";
 
 const CHANGE = "change";
@@ -158,3 +158,8 @@ export class VirtualArray<T> extends Observable implements virtualArrayDef.Virtu
         }
     }
 }
+export interface VirtualArray<T> {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any);
+    on(event: "itemsLoading", callback: (args: virtualArrayDef.ItemsLoading) => void, thisArg?: any);
+    on(event: "change", callback: (args: virtualArrayDef.ChangedData<T>) => void, thisArg?: any);
+}
diff --git a/tns-core-modules/globals/globals.ts b/tns-core-modules/globals/globals.ts
index d4b5ed6f9..6e8416a12 100644
--- a/tns-core-modules/globals/globals.ts
+++ b/tns-core-modules/globals/globals.ts
@@ -23,7 +23,7 @@ global.moduleMerge = function (sourceExports: any, destExports: any) {
 import * as timerModule from "../timer";
 import * as dialogsModule from "../ui/dialogs";
 
-type ModuleLoader = () => any;
+type ModuleLoader = (name?: string) => any;
 const modules: Map<string, ModuleLoader> = new Map<string, ModuleLoader>();
 
 global.registerModule = function(name: string, loader: ModuleLoader): void {
diff --git a/tns-core-modules/image-source/image-source.android.ts b/tns-core-modules/image-source/image-source.android.ts
index 0b7c3ec64..7fb8029a8 100644
--- a/tns-core-modules/image-source/image-source.android.ts
+++ b/tns-core-modules/image-source/image-source.android.ts
@@ -242,7 +242,7 @@ export function fromNativeSource(source: any): ImageSource {
     return image.setNativeSource(source) ? image : null;
 }
 
-export function fromUrl(url: string): Promise<ImageSource> {
+export function fromUrl(url: string): Promise<ImageSourceDefinition> {
     ensureHttp();
     return http.getImage(url);
 }
diff --git a/tns-core-modules/profiling/profiling.ts b/tns-core-modules/profiling/profiling.ts
index 5a49fa1aa..c1daaa488 100644
--- a/tns-core-modules/profiling/profiling.ts
+++ b/tns-core-modules/profiling/profiling.ts
@@ -161,7 +161,7 @@ const profileMethodUnnamed = (target, key, descriptor) => {
 }
 
 function profileMethodNamed(name: string): MethodDecorator {
-    return (target, key, descriptor) => {
+    return (target, key, descriptor: PropertyDescriptor) => {
 
         // save a reference to the original method this way we keep the values currently in the
         // descriptor and don't overwrite what another decorator might have done to the descriptor.
diff --git a/tns-core-modules/ui/core/properties/properties.d.ts b/tns-core-modules/ui/core/properties/properties.d.ts
index 8e8dabed3..2203721a8 100644
--- a/tns-core-modules/ui/core/properties/properties.d.ts
+++ b/tns-core-modules/ui/core/properties/properties.d.ts
@@ -45,7 +45,7 @@ export interface CssAnimationPropertyOptions<T, U> {
     readonly valueConverter?: (value: string) => U;
 }
 
-export class Property<T extends ViewBase, U> implements TypedPropertyDescriptor<U> {
+export class Property<T extends ViewBase, U> {
     constructor(options: PropertyOptions<T, U>);
 
     public readonly getDefault: symbol;
@@ -55,12 +55,16 @@ export class Property<T extends ViewBase, U> implements TypedPropertyDescriptor<
     public nativeValueChange(T, U): void;
     public isSet(instance: T): boolean;
 }
+export interface Property<T extends ViewBase, U> extends TypedPropertyDescriptor<U> {
+}
 
-export class CoercibleProperty<T extends ViewBase, U> extends Property<T, U> implements TypedPropertyDescriptor<U> {
+export class CoercibleProperty<T extends ViewBase, U> extends Property<T, U> {
     constructor(options: CoerciblePropertyOptions<T, U>);
 
     public readonly coerce: (target: T) => void;
 }
+export interface CoercibleProperty<T extends ViewBase, U> extends TypedPropertyDescriptor<U> {
+}
 
 export class InheritedProperty<T extends ViewBase, U> extends Property<T, U> {
     constructor(options: PropertyOptions<T, U>);
diff --git a/tns-core-modules/ui/dialogs/dialogs.d.ts b/tns-core-modules/ui/dialogs/dialogs.d.ts
index 4d58c8252..f9a96d660 100644
--- a/tns-core-modules/ui/dialogs/dialogs.d.ts
+++ b/tns-core-modules/ui/dialogs/dialogs.d.ts
@@ -27,7 +27,7 @@ export module inputType {
  * The alert() method displays an alert box with a specified message.
  * @param message Specifies the text to display in the alert box.
  */
-export function alert(message: string): Promise<void>;
+export function alert(message: string | number | boolean): Promise<void>;
 
 /**
  * The alert() method displays an alert box with a specified message.
diff --git a/tns-core-modules/ui/image-cache/image-cache-common.ts b/tns-core-modules/ui/image-cache/image-cache-common.ts
index e5feaf70f..b505a390d 100644
--- a/tns-core-modules/ui/image-cache/image-cache-common.ts
+++ b/tns-core-modules/ui/image-cache/image-cache-common.ts
@@ -184,3 +184,7 @@ export class Cache extends observable.Observable implements definition.Cache {
         this._download(request);
     }
 }
+export interface Cache {
+    on(eventNames: string, callback: (args: observable.EventData) => void , thisArg?: any);
+    on(event: "downloaded", callback: (args: definition.DownloadedData) => void , thisArg?: any);
+}
\ No newline at end of file
diff --git a/tns-core-modules/ui/list-view/list-view-common.ts b/tns-core-modules/ui/list-view/list-view-common.ts
index 89856b5e6..66b45d035 100644
--- a/tns-core-modules/ui/list-view/list-view-common.ts
+++ b/tns-core-modules/ui/list-view/list-view-common.ts
@@ -1,5 +1,5 @@
-import { ListView as ListViewDefinition, ItemsSource } from ".";
-import { CoercibleProperty, CssProperty, Style, View, Template, KeyedTemplate, Length, Property, Color, Observable } from "../core/view";
+import { ListView as ListViewDefinition, ItemsSource, ItemEventData } from ".";
+import { CoercibleProperty, CssProperty, Style, View, Template, KeyedTemplate, Length, Property, Color, Observable, EventData } from "../core/view";
 import { parse, parseMultipleTemplates } from "../builder";
 import { Label } from "../label";
 import { ObservableArray, ChangedData } from "../../data/observable-array";
@@ -129,9 +129,15 @@ export abstract class ListViewBase extends View implements ListViewDefinition {
         rowHeightProperty.coerce(this);
     }
 }
-
 ListViewBase.prototype.recycleNativeView = true;
 
+export interface ListViewBase {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any);
+    on(event: "itemLoading", callback: (args: ItemEventData) => void, thisArg?: any);
+    on(event: "itemTap", callback: (args: ItemEventData) => void, thisArg?: any);
+    on(event: "loadMoreItems", callback: (args: EventData) => void, thisArg?: any);
+}
+
 /**
  * Represents the property backing the items property of each ListView instance.
  */
diff --git a/tns-core-modules/ui/page/page-common.ts b/tns-core-modules/ui/page/page-common.ts
index c8bddc4d5..86fd8289f 100644
--- a/tns-core-modules/ui/page/page-common.ts
+++ b/tns-core-modules/ui/page/page-common.ts
@@ -1,7 +1,7 @@
 import { Page as PageDefinition, NavigatedData, ShownModallyData } from ".";
 import {
     ContentView, View, eachDescendant, Property, CssProperty, Color, isIOS,
-    booleanConverter, resetCSSProperties, Style
+    booleanConverter, resetCSSProperties, Style, EventData
 } from "../content-view";
 import { Frame, topmost as topmostFrame, resolvePageFromEntry } from "../frame";
 import { ActionBar } from "../action-bar";
@@ -297,6 +297,15 @@ export class PageBase extends ContentView implements PageDefinition {
         eachDescendant(this, resetCssValuesFunc);
     }
 }
+export interface PageBase {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any): void;
+    on(event: "navigatingTo", callback: (args: NavigatedData) => void, thisArg?: any): void;
+    on(event: "navigatedTo", callback: (args: NavigatedData) => void, thisArg?: any): void;
+    on(event: "navigatingFrom", callback: (args: NavigatedData) => void, thisArg?: any): void;
+    on(event: "navigatedFrom", callback: (args: NavigatedData) => void, thisArg?: any): void;
+    on(event: "showingModally", callback: (args: ShownModallyData) => void, thisArg?: any): void;
+    on(event: "shownModally", callback: (args: ShownModallyData) => void, thisArg?: any);
+}
 
 /**
  * Dependency property used to hide the Navigation Bar in iOS and the Action Bar in Android.
diff --git a/tns-core-modules/ui/placeholder/placeholder.android.ts b/tns-core-modules/ui/placeholder/placeholder.android.ts
index f3a79c7ac..c3fe38543 100644
--- a/tns-core-modules/ui/placeholder/placeholder.android.ts
+++ b/tns-core-modules/ui/placeholder/placeholder.android.ts
@@ -1,5 +1,5 @@
 import { Placeholder as PlaceholderDefinition, CreateViewEventData } from "."
-import { View } from "../core/view"
+import { View, EventData } from "../core/view"
 
 export class Placeholder extends View implements PlaceholderDefinition {
     public static creatingViewEvent = "creatingView";
@@ -9,4 +9,8 @@ export class Placeholder extends View implements PlaceholderDefinition {
         this.notify(args);
         return <android.view.View>args.view;
     }
+}
+export interface Placeholder {
+    on(eventNames: string, callback: (args: EventData) => void);
+    on(event: "creatingView", callback: (args: CreateViewEventData) => void);
 }
\ No newline at end of file
diff --git a/tns-core-modules/ui/placeholder/placeholder.ts b/tns-core-modules/ui/placeholder/placeholder.ts
index b986756c8..271aab412 100644
--- a/tns-core-modules/ui/placeholder/placeholder.ts
+++ b/tns-core-modules/ui/placeholder/placeholder.ts
@@ -1,5 +1,5 @@
 import { Placeholder as PlaceholderDefinition, CreateViewEventData } from "."
-import { View } from "../core/view"
+import { View, EventData } from "../core/view"
 
 export class Placeholder extends View implements PlaceholderDefinition {
     public static creatingViewEvent = "creatingView";
@@ -9,4 +9,8 @@ export class Placeholder extends View implements PlaceholderDefinition {
         this.notify(args);
         return args.view;
     }
+}
+export interface Placeholder {
+    on(eventNames: string, callback: (args: EventData) => void);
+    on(event: "creatingView", callback: (args: CreateViewEventData) => void);
 }
\ No newline at end of file
diff --git a/tns-core-modules/ui/scroll-view/scroll-view-common.ts b/tns-core-modules/ui/scroll-view/scroll-view-common.ts
index f0dabf7ac..68109b2a4 100644
--- a/tns-core-modules/ui/scroll-view/scroll-view-common.ts
+++ b/tns-core-modules/ui/scroll-view/scroll-view-common.ts
@@ -1,5 +1,5 @@
-import { ScrollView as ScrollViewDefinition, Orientation } from ".";
-import { ContentView, Property, makeParser, makeValidator } from "../content-view";
+import { ScrollView as ScrollViewDefinition, Orientation, ScrollEventData } from ".";
+import { ContentView, Property, makeParser, makeValidator, EventData } from "../content-view";
 import { profile } from "../../profiling";
 
 export * from "../content-view";
@@ -81,6 +81,10 @@ export abstract class ScrollViewBase extends ContentView implements ScrollViewDe
     public abstract scrollToHorizontalOffset(value: number, animated: boolean);
     public abstract _onOrientationChanged();
 }
+export interface ScrollViewBase {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any);
+    on(event: "scroll", callback: (args: ScrollEventData) => void, thisArg?: any);
+}
 
 const converter = makeParser<Orientation>(makeValidator("horizontal", "vertical"));
 export const orientationProperty = new Property<ScrollViewBase, Orientation>({
diff --git a/tns-core-modules/ui/segmented-bar/segmented-bar-common.ts b/tns-core-modules/ui/segmented-bar/segmented-bar-common.ts
index 4d6f2ab99..11eda4db0 100644
--- a/tns-core-modules/ui/segmented-bar/segmented-bar-common.ts
+++ b/tns-core-modules/ui/segmented-bar/segmented-bar-common.ts
@@ -1,7 +1,7 @@
 import { SegmentedBar as SegmentedBarDefinition, SegmentedBarItem as SegmentedBarItemDefinition, SelectedIndexChangedEventData } from ".";
 import {
     ViewBase, View, AddChildFromBuilder, AddArrayFromBuilder,
-    Property, CoercibleProperty, InheritedCssProperty, Color, Style
+    Property, CoercibleProperty, InheritedCssProperty, Color, Style, EventData
 } from "../core/view";
 
 export * from "../core/view";
@@ -89,6 +89,10 @@ export abstract class SegmentedBarBase extends View implements SegmentedBarDefin
         }
     }
 }
+export interface SegmentedBarBase {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any);
+    on(event: "selectedIndexChanged", callback: (args: SelectedIndexChangedEventData) => void, thisArg?: any);
+}
 
 SegmentedBarBase.prototype.recycleNativeView = true;
 
diff --git a/tns-core-modules/ui/tab-view/tab-view-common.ts b/tns-core-modules/ui/tab-view/tab-view-common.ts
index 92fbe988d..8b3a6750b 100644
--- a/tns-core-modules/ui/tab-view/tab-view-common.ts
+++ b/tns-core-modules/ui/tab-view/tab-view-common.ts
@@ -1,7 +1,7 @@
 import { TabView as TabViewDefinition, TabViewItem as TabViewItemDefinition, SelectedIndexChangedEventData } from ".";
 import {
     View, ViewBase, Style, Property, CssProperty, CoercibleProperty,
-    Color, isIOS, AddArrayFromBuilder, AddChildFromBuilder
+    Color, isIOS, AddArrayFromBuilder, AddChildFromBuilder, EventData
 } from "../core/view";
 
 export * from "../core/view";
@@ -182,6 +182,10 @@ export class TabViewBase extends View implements TabViewDefinition, AddChildFrom
         }
     }
 }
+export interface TabViewBase {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any);
+    on(event: "selectedIndexChanged", callback: (args: SelectedIndexChangedEventData) => void, thisArg?: any);
+}
 
 export const selectedIndexProperty = new CoercibleProperty<TabViewBase, number>({
     name: "selectedIndex", defaultValue: -1, affectsLayout: isIOS,
diff --git a/tns-core-modules/ui/web-view/web-view-common.ts b/tns-core-modules/ui/web-view/web-view-common.ts
index 9931ac45b..24a04e61b 100644
--- a/tns-core-modules/ui/web-view/web-view-common.ts
+++ b/tns-core-modules/ui/web-view/web-view-common.ts
@@ -1,5 +1,5 @@
 import { WebView as WebViewDefinition, LoadEventData, NavigationType } from ".";
-import { View, Property } from "../core/view";
+import { View, Property, EventData } from "../core/view";
 import { File, knownFolders, path } from "../../file-system";
 
 export { File, knownFolders, path, NavigationType };
@@ -92,5 +92,10 @@ export abstract class WebViewBase extends View implements WebViewDefinition {
         throw new Error("Property url of WebView is deprecated. Use src instead")
     }
 }
+export interface WebViewBase {
+    on(eventNames: string, callback: (data: EventData) => void, thisArg?: any);
+    on(event: "loadFinished", callback: (args: LoadEventData) => void, thisArg?: any);
+    on(event: "loadStarted", callback: (args: LoadEventData) => void, thisArg?: any);
+}
 
 srcProperty.register(WebViewBase);
diff --git a/tns-platform-declarations/android/android17.d.ts b/tns-platform-declarations/android/android17.d.ts
index 66224c830..b9c94883c 100644
--- a/tns-platform-declarations/android/android17.d.ts
+++ b/tns-platform-declarations/android/android17.d.ts
@@ -107930,7 +107930,6 @@ declare module javax {
 					glQueryMatrixxOES(mantissa: java.nio.IntBuffer, exponent: java.nio.IntBuffer): number;
 				}
 				interface IGL {
-					__javax_microedition_khronos_opengles_IGL?: any;
 				}
 			}
 			export module egl {
@@ -107939,7 +107938,6 @@ declare module javax {
 					static class: java.lang.Class<javax.microedition.khronos.egl.EGLSurface>;
 				}
 				interface IEGL {
-					__javax_microedition_khronos_egl_IEGL?: any;
 				}
 				export class EGL10 implements javax.microedition.khronos.egl.IEGL, javax.microedition.khronos.egl.IEGL10 {
 					constructor(implementation: javax.microedition.khronos.egl.IEGL10);