diff --git a/.gitignore b/.gitignore
index 4a4c99b4f3e..06c00d62e84 100644
--- a/.gitignore
+++ b/.gitignore
@@ -54,3 +54,4 @@ npm-debug.log
 # couple of the files. Once it is, we can switch this over to just ignoring
 # `types/stable` entirely.
 types/stable
+.puppeteer-cache/
diff --git a/package.json b/package.json
index b01ee55a34f..6d0acd143dc 100644
--- a/package.json
+++ b/package.json
@@ -211,6 +211,7 @@
       "@ember/-internals/views/lib/mixins/action_support.js": "ember-source/@ember/-internals/views/lib/mixins/action_support.js",
       "@ember/-internals/views/lib/system/event_dispatcher.js": "ember-source/@ember/-internals/views/lib/system/event_dispatcher.js",
       "@ember/-internals/views/lib/system/utils.js": "ember-source/@ember/-internals/views/lib/system/utils.js",
+      "@ember/-internals/views/lib/views/core-view-utils.js": "ember-source/@ember/-internals/views/lib/views/core-view-utils.js",
       "@ember/-internals/views/lib/views/core_view.js": "ember-source/@ember/-internals/views/lib/views/core_view.js",
       "@ember/-internals/views/lib/views/states.js": "ember-source/@ember/-internals/views/lib/views/states.js",
       "@ember/application/index.js": "ember-source/@ember/application/index.js",
diff --git a/packages/@ember/-internals/deprecations/index.ts b/packages/@ember/-internals/deprecations/index.ts
index 89ad88ed625..ac5395192c5 100644
--- a/packages/@ember/-internals/deprecations/index.ts
+++ b/packages/@ember/-internals/deprecations/index.ts
@@ -20,7 +20,7 @@ export function isRemoved(options: DeprecationOptions) {
   return emberVersionGte(options.until);
 }
 
-interface DeprecationObject {
+export interface DeprecationObject {
   options: DeprecationOptions;
   test: boolean;
   isEnabled: boolean;
@@ -122,6 +122,13 @@ export const DEPRECATIONS = {
     until: '7.0.0',
     url: 'https://deprecations.emberjs.com/id/using-amd-bundles',
   }),
+  DEPRECATE_EVENTED: deprecation({
+    id: 'ember-evented',
+    for: 'ember-source',
+    since: { available: '6.12.0' },
+    until: '8.0.0',
+    url: 'https://deprecations.emberjs.com/id/ember-evented',
+  }),
 };
 
 export function deprecateUntil(message: string, deprecation: DeprecationObject) {
diff --git a/packages/@ember/-internals/glimmer/lib/component-managers/curly.ts b/packages/@ember/-internals/glimmer/lib/component-managers/curly.ts
index 0b0da6ec97d..7021b4c8d3d 100644
--- a/packages/@ember/-internals/glimmer/lib/component-managers/curly.ts
+++ b/packages/@ember/-internals/glimmer/lib/component-managers/curly.ts
@@ -5,7 +5,12 @@ import {
   setOwner,
 } from '@ember/-internals/owner';
 import { enumerableSymbol, guidFor } from '@ember/-internals/utils';
-import { addChildView, setElementView, setViewElement } from '@ember/-internals/views';
+import {
+  addChildView,
+  sendCoreViewEvent,
+  setElementView,
+  setViewElement,
+} from '@ember/-internals/views';
 import type { Nullable } from '@ember/-internals/utility-types';
 import { assert, debugFreeze } from '@ember/debug';
 import { _instrumentStart } from '@ember/instrumentation';
@@ -305,20 +310,20 @@ export default class CurlyComponentManager
       addChildView(parentView, component);
     }
 
-    component.trigger('didReceiveAttrs');
+    sendCoreViewEvent(component, 'didReceiveAttrs');
 
     let hasWrappedElement = component.tagName !== '';
 
     // We usually do this in the `didCreateElement`, but that hook doesn't fire for tagless components
     if (!hasWrappedElement) {
       if (isInteractive) {
-        component.trigger('willRender');
+        sendCoreViewEvent(component, 'willRender');
       }
 
       component._transitionTo('hasElement');
 
       if (isInteractive) {
-        component.trigger('willInsertElement');
+        sendCoreViewEvent(component, 'willInsertElement');
       }
     }
 
@@ -342,7 +347,7 @@ export default class CurlyComponentManager
     }
 
     if (isInteractive && hasWrappedElement) {
-      component.trigger('willRender');
+      sendCoreViewEvent(component, 'willRender');
     }
 
     endUntrackFrame();
@@ -407,7 +412,7 @@ export default class CurlyComponentManager
 
     if (isInteractive) {
       beginUntrackFrame();
-      component.trigger('willInsertElement');
+      sendCoreViewEvent(component, 'willInsertElement');
       endUntrackFrame();
     }
   }
@@ -420,8 +425,8 @@ export default class CurlyComponentManager
   didCreate({ component, isInteractive }: ComponentStateBucket): void {
     if (isInteractive) {
       component._transitionTo('inDOM');
-      component.trigger('didInsertElement');
-      component.trigger('didRender');
+      sendCoreViewEvent(component, 'didInsertElement');
+      sendCoreViewEvent(component, 'didRender');
     }
   }
 
@@ -443,13 +448,13 @@ export default class CurlyComponentManager
       component.setProperties(props);
       component[IS_DISPATCHING_ATTRS] = false;
 
-      component.trigger('didUpdateAttrs');
-      component.trigger('didReceiveAttrs');
+      sendCoreViewEvent(component, 'didUpdateAttrs');
+      sendCoreViewEvent(component, 'didReceiveAttrs');
     }
 
     if (isInteractive) {
-      component.trigger('willUpdate');
-      component.trigger('willRender');
+      sendCoreViewEvent(component, 'willUpdate');
+      sendCoreViewEvent(component, 'willRender');
     }
 
     endUntrackFrame();
@@ -464,8 +469,8 @@ export default class CurlyComponentManager
 
   didUpdate({ component, isInteractive }: ComponentStateBucket): void {
     if (isInteractive) {
-      component.trigger('didUpdate');
-      component.trigger('didRender');
+      sendCoreViewEvent(component, 'didUpdate');
+      sendCoreViewEvent(component, 'didRender');
     }
   }
 
diff --git a/packages/@ember/-internals/glimmer/lib/component-managers/root.ts b/packages/@ember/-internals/glimmer/lib/component-managers/root.ts
index 00aca8f633c..2edd819fde1 100644
--- a/packages/@ember/-internals/glimmer/lib/component-managers/root.ts
+++ b/packages/@ember/-internals/glimmer/lib/component-managers/root.ts
@@ -20,6 +20,7 @@ import CurlyComponentManager, {
   initialRenderInstrumentDetails,
   processComponentInitializationAssertions,
 } from './curly';
+import { sendCoreViewEvent } from '@ember/-internals/views';
 
 class RootComponentManager extends CurlyComponentManager {
   component: Component;
@@ -47,13 +48,13 @@ class RootComponentManager extends CurlyComponentManager {
     // We usually do this in the `didCreateElement`, but that hook doesn't fire for tagless components
     if (!hasWrappedElement) {
       if (isInteractive) {
-        component.trigger('willRender');
+        sendCoreViewEvent(component, 'willRender');
       }
 
       component._transitionTo('hasElement');
 
       if (isInteractive) {
-        component.trigger('willInsertElement');
+        sendCoreViewEvent(component, 'willInsertElement');
       }
     }
 
diff --git a/packages/@ember/-internals/glimmer/lib/renderer.ts b/packages/@ember/-internals/glimmer/lib/renderer.ts
index 2a0847d4818..6cb7976a4b0 100644
--- a/packages/@ember/-internals/glimmer/lib/renderer.ts
+++ b/packages/@ember/-internals/glimmer/lib/renderer.ts
@@ -3,7 +3,7 @@ import { ENV } from '@ember/-internals/environment';
 import type { InternalOwner } from '@ember/-internals/owner';
 import { getOwner } from '@ember/-internals/owner';
 import { guidFor } from '@ember/-internals/utils';
-import { getViewElement, getViewId } from '@ember/-internals/views';
+import { getViewElement, getViewId, sendCoreViewEvent } from '@ember/-internals/views';
 import { assert } from '@ember/debug';
 import { _backburner, _getCurrentRunLoop } from '@ember/runloop';
 import {
@@ -917,7 +917,7 @@ export class Renderer extends BaseRenderer {
     this.cleanupRootFor(view);
 
     if (this.state.isInteractive) {
-      view.trigger('didDestroyElement');
+      sendCoreViewEvent(view, 'didDestroyElement');
     }
   }
 
diff --git a/packages/@ember/-internals/glimmer/lib/utils/curly-component-state-bucket.ts b/packages/@ember/-internals/glimmer/lib/utils/curly-component-state-bucket.ts
index 5a4fb529a6f..e07d740200f 100644
--- a/packages/@ember/-internals/glimmer/lib/utils/curly-component-state-bucket.ts
+++ b/packages/@ember/-internals/glimmer/lib/utils/curly-component-state-bucket.ts
@@ -1,4 +1,9 @@
-import { clearElementView, clearViewElement, getViewElement } from '@ember/-internals/views';
+import {
+  clearElementView,
+  clearViewElement,
+  getViewElement,
+  sendCoreViewEvent,
+} from '@ember/-internals/views';
 import { registerDestructor } from '@glimmer/destroyable';
 import type { CapturedNamedArguments } from '@glimmer/interfaces';
 import type { Reference } from '@glimmer/reference';
@@ -46,8 +51,8 @@ export default class ComponentStateBucket {
 
     if (isInteractive) {
       beginUntrackFrame();
-      component.trigger('willDestroyElement');
-      component.trigger('willClearRender');
+      sendCoreViewEvent(component, 'willDestroyElement');
+      sendCoreViewEvent(component, 'willClearRender');
       endUntrackFrame();
 
       let element = getViewElement(component);
diff --git a/packages/@ember/-internals/glimmer/tests/integration/components/append-test.js b/packages/@ember/-internals/glimmer/tests/integration/components/append-test.js
index 3e89c2297a3..17df9c34069 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/components/append-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/components/append-test.js
@@ -1,4 +1,12 @@
-import { moduleFor, RenderingTestCase, strip, runTask } from 'internal-test-helpers';
+import {
+  moduleFor,
+  RenderingTestCase,
+  strip,
+  runTask,
+  expectDeprecation,
+  testUnless,
+} from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../../../deprecations';
 
 import { set } from '@ember/object';
 
@@ -38,7 +46,9 @@ class AbstractAppendTest extends RenderingTestCase {
     this.ids.push(component.elementId);
   }
 
-  [`@test (new) lifecycle hooks during component append`](assert) {
+  [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test (new) lifecycle hooks during component append`](
+    assert
+  ) {
     let hooks = [];
 
     let componentsByName = {};
@@ -56,7 +66,13 @@ class AbstractAppendTest extends RenderingTestCase {
           }
           componentsByName[name] = this;
           pushHook('init');
-          this.on('init', () => pushHook('on(init)'));
+          expectDeprecation(
+            () => {
+              this.on('init', () => pushHook('on(init)'));
+            },
+            /Evented#on` is deprecated/,
+            DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+          );
         }
 
         didReceiveAttrs() {
@@ -278,7 +294,9 @@ class AbstractAppendTest extends RenderingTestCase {
     );
   }
 
-  [`@test lifecycle hooks during component append`](assert) {
+  [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test lifecycle hooks during component append`](
+    assert
+  ) {
     let hooks = [];
 
     let oldRegisterComponent = this.registerComponent;
@@ -299,7 +317,13 @@ class AbstractAppendTest extends RenderingTestCase {
             }
             componentsByName[name] = this;
             pushHook('init');
-            this.on('init', () => pushHook('on(init)'));
+            expectDeprecation(
+              () => {
+                this.on('init', () => pushHook('on(init)'));
+              },
+              /Evented#on` is deprecated/,
+              DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+            );
           }
 
           didReceiveAttrs() {
diff --git a/packages/@ember/-internals/glimmer/tests/integration/components/curly-components-test.js b/packages/@ember/-internals/glimmer/tests/integration/components/curly-components-test.js
index 2bf955d092e..45e8a361702 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/components/curly-components-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/components/curly-components-test.js
@@ -7,7 +7,10 @@ import {
   equalsElement,
   runTask,
   runLoopSettled,
+  expectDeprecation,
+  testUnless,
 } from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../../../deprecations';
 
 import { action } from '@ember/object';
 import { run } from '@ember/runloop';
@@ -3159,48 +3162,60 @@ moduleFor(
       runTask(() => set(this.context, 'foo', 5));
     }
 
-    ['@test triggering an event only attempts to invoke an identically named method, if it actually is a function (GH#15228)'](
+    [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test triggering an event only attempts to invoke an identically named method, if it actually is a function (GH#15228)`](
       assert
     ) {
-      assert.expect(3);
+      assert.expect(5);
 
       let payload = ['arbitrary', 'event', 'data'];
 
-      this.registerComponent('evented-component', {
-        ComponentClass: Component.extend({
-          someTruthyProperty: true,
-
-          init() {
-            this._super(...arguments);
-            this.trigger('someMethod', ...payload);
-            this.trigger('someTruthyProperty', ...payload);
-          },
-
-          someMethod(...data) {
-            assert.deepEqual(
-              data,
-              payload,
-              'the method `someMethod` should be called, when `someMethod` is triggered'
-            );
-          },
-
-          listenerForSomeMethod: on('someMethod', function (...data) {
-            assert.deepEqual(
-              data,
-              payload,
-              'the listener `listenerForSomeMethod` should be called, when `someMethod` is triggered'
-            );
-          }),
-
-          listenerForSomeTruthyProperty: on('someTruthyProperty', function (...data) {
-            assert.deepEqual(
-              data,
-              payload,
-              'the listener `listenerForSomeTruthyProperty` should be called, when `someTruthyProperty` is triggered'
-            );
-          }),
-        }),
-      });
+      expectDeprecation(
+        () => {
+          this.registerComponent('evented-component', {
+            ComponentClass: Component.extend({
+              someTruthyProperty: true,
+
+              init() {
+                this._super(...arguments);
+                expectDeprecation(
+                  () => {
+                    this.trigger('someMethod', ...payload);
+                    this.trigger('someTruthyProperty', ...payload);
+                  },
+                  /Evented#trigger` is deprecated/,
+                  DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+                );
+              },
+
+              someMethod(...data) {
+                assert.deepEqual(
+                  data,
+                  payload,
+                  'the method `someMethod` should be called, when `someMethod` is triggered'
+                );
+              },
+
+              listenerForSomeMethod: on('someMethod', function (...data) {
+                assert.deepEqual(
+                  data,
+                  payload,
+                  'the listener `listenerForSomeMethod` should be called, when `someMethod` is triggered'
+                );
+              }),
+
+              listenerForSomeTruthyProperty: on('someTruthyProperty', function (...data) {
+                assert.deepEqual(
+                  data,
+                  payload,
+                  'the listener `listenerForSomeTruthyProperty` should be called, when `someTruthyProperty` is triggered'
+                );
+              }),
+            }),
+          });
+        },
+        /`on\(\)` event decorator is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       this.render(`{{evented-component}}`);
     }
diff --git a/packages/@ember/-internals/glimmer/tests/integration/components/life-cycle-test.js b/packages/@ember/-internals/glimmer/tests/integration/components/life-cycle-test.js
index 1c4f3bed6c0..e953ffef663 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/components/life-cycle-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/components/life-cycle-test.js
@@ -6,6 +6,7 @@ import { A as emberA } from '@ember/array';
 import { getViewElement, getViewId } from '@ember/-internals/views';
 
 import { Component } from '../../utils/helpers';
+import { addListener } from '@ember/-internals/metal';
 
 class LifeCycleHooksTest extends RenderingTestCase {
   constructor() {
@@ -174,7 +175,7 @@ class LifeCycleHooksTest extends RenderingTestCase {
         assertNoElement('init', this);
         assertState('init', 'preRender', this);
 
-        this.on('init', () => pushHook('on(init)'));
+        addListener(this, 'init', () => pushHook('on(init)'));
 
         schedule('afterRender', () => {
           this.isInitialRender = false;
diff --git a/packages/@ember/-internals/glimmer/tests/integration/event-dispatcher-test.js b/packages/@ember/-internals/glimmer/tests/integration/event-dispatcher-test.js
index 60c37711e7d..7a40f1f169d 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/event-dispatcher-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/event-dispatcher-test.js
@@ -1,4 +1,11 @@
-import { moduleFor, RenderingTestCase, runTask } from 'internal-test-helpers';
+import {
+  expectDeprecation,
+  moduleFor,
+  RenderingTestCase,
+  runTask,
+  testUnless,
+} from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../../deprecations';
 
 import { Component } from '../utils/helpers';
 import { _getCurrentRunLoop } from '@ember/runloop';
@@ -149,7 +156,9 @@ moduleFor(
       }
     }
 
-    ['@test event listeners are called when event is triggered'](assert) {
+    [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test event listeners are called when event is triggered`](
+      assert
+    ) {
       let receivedEvent;
       let browserEvent;
 
@@ -159,7 +168,13 @@ moduleFor(
           init() {
             super.init();
             Object.keys(SUPPORTED_EMBER_EVENTS).forEach((browserEvent) => {
-              this.on(SUPPORTED_EMBER_EVENTS[browserEvent], (event) => (receivedEvent = event));
+              expectDeprecation(
+                () => {
+                  this.on(SUPPORTED_EMBER_EVENTS[browserEvent], (event) => (receivedEvent = event));
+                },
+                /Evented#on` is deprecated/,
+                DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+              );
             });
           }
         },
diff --git a/packages/@ember/-internals/glimmer/tests/integration/syntax/each-test.js b/packages/@ember/-internals/glimmer/tests/integration/syntax/each-test.js
index e4ed8e69213..3c704fffbda 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/syntax/each-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/syntax/each-test.js
@@ -1,4 +1,12 @@
-import { moduleFor, RenderingTestCase, applyMixins, strip, runTask } from 'internal-test-helpers';
+import {
+  moduleFor,
+  RenderingTestCase,
+  applyMixins,
+  strip,
+  runTask,
+  expectDeprecation,
+} from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../../../deprecations';
 
 import { notifyPropertyChange, on } from '@ember/-internals/metal';
 import { get, set, computed } from '@ember/object';
@@ -1116,21 +1124,30 @@ moduleFor(
   }
 );
 
-moduleFor(
-  'Syntax test: {{#each}} with array proxies, content is updated after init',
-  class extends EachTest {
-    createList(items) {
-      let wrapped = emberA(items);
-      let proxy = ArrayProxy.extend({
-        setup: on('init', function () {
-          this.set('content', emberA(wrapped));
-        }),
-      }).create();
+if (!DEPRECATIONS.DEPRECATE_EVENTED.isRemoved) {
+  moduleFor(
+    'Syntax test: {{#each}} with array proxies, content is updated after init',
+    class extends EachTest {
+      createList(items) {
+        let wrapped = emberA(items);
+        let proxy;
+        expectDeprecation(
+          () => {
+            proxy = ArrayProxy.extend({
+              setup: on('init', function () {
+                this.set('content', emberA(wrapped));
+              }),
+            }).create();
+          },
+          /`on\(\)` event decorator is deprecated/,
+          DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+        );
 
-      return { list: proxy, delegate: wrapped };
+        return { list: proxy, delegate: wrapped };
+      }
     }
-  }
-);
+  );
+}
 
 moduleFor(
   'Syntax test: {{#each as}} undefined path',
diff --git a/packages/@ember/-internals/meta/lib/meta.ts b/packages/@ember/-internals/meta/lib/meta.ts
index 7d429b5f13e..c366af2c88a 100644
--- a/packages/@ember/-internals/meta/lib/meta.ts
+++ b/packages/@ember/-internals/meta/lib/meta.ts
@@ -355,7 +355,7 @@ export class Meta {
   addToListeners(
     eventName: string,
     target: object | null,
-    method: Function | PropertyKey,
+    method: ((...args: any[]) => void) | PropertyKey,
     once: boolean,
     sync: boolean
   ) {
diff --git a/packages/@ember/-internals/metal/lib/events.ts b/packages/@ember/-internals/metal/lib/events.ts
index ab77fb52c86..eb6a645a7bd 100644
--- a/packages/@ember/-internals/metal/lib/events.ts
+++ b/packages/@ember/-internals/metal/lib/events.ts
@@ -6,6 +6,7 @@ import { meta as metaFor, peekMeta } from '@ember/-internals/meta';
 import { setListeners } from '@ember/-internals/utils';
 import type { AnyFn } from '@ember/-internals/utility-types';
 import { assert } from '@ember/debug';
+import { DEPRECATIONS, deprecateUntil } from '@ember/-internals/deprecations';
 
 /*
   The event system uses a series of nested hashes to store listeners on an
@@ -38,11 +39,24 @@ import { assert } from '@ember/debug';
   @param {Boolean} once A flag whether a function should only be called once
   @public
 */
+export function addListener<Target>(
+  obj: object,
+  eventName: string,
+  target: Target,
+  method: PropertyKey | ((this: Target, ...args: any[]) => void),
+  once?: boolean,
+  sync?: boolean
+): void;
+export function addListener(
+  obj: object,
+  eventName: string,
+  method: PropertyKey | ((...args: any[]) => void)
+): void;
 export function addListener(
   obj: object,
   eventName: string,
-  target: object | Function | null,
-  method?: Function | PropertyKey,
+  target: object | PropertyKey | ((...args: any[]) => void) | null,
+  method?: PropertyKey | ((...args: any[]) => void),
   once?: boolean,
   sync = true
 ): void {
@@ -52,10 +66,13 @@ export function addListener(
   );
 
   if (!method && 'function' === typeof target) {
-    method = target;
+    // SAFETY: This should be correct. It may be possible to get TS to infer it.
+    method = target as (...args: any[]) => void;
     target = null;
   }
 
+  assert('target should be object or null', target === null || typeof target === 'object');
+
   metaFor(obj).addToListeners(eventName, target, method!, once === true, sync);
 }
 
@@ -76,8 +93,19 @@ export function addListener(
 export function removeListener(
   obj: object,
   eventName: string,
-  targetOrFunction: object | Function | null,
-  functionOrName?: string | Function
+  target: object | null,
+  methodOrName: string | ((...args: any[]) => void)
+): void;
+export function removeListener(
+  obj: object,
+  eventName: string,
+  method: (...args: any[]) => void
+): void;
+export function removeListener(
+  obj: object,
+  eventName: string,
+  targetOrFunction: object | ((...args: any[]) => void) | null,
+  functionOrName?: string | ((...args: any[]) => void)
 ): void {
   assert(
     'You must pass at least an object, event name, and method or target and method/method name to removeListener',
@@ -143,7 +171,7 @@ export function sendEvent(
       continue;
     }
     if (once) {
-      removeListener(obj, eventName, target, method);
+      removeListener(obj, eventName, target, method as string | ((...args: any[]) => void));
     }
     if (!target) {
       target = obj;
@@ -199,6 +227,7 @@ export function hasListeners(obj: object, eventName: string): boolean {
 
   @method on
   @static
+  @deprecated Use native JavaScript events or a dedicated event library instead.
   @for @ember/object/evented
   @param {String} eventNames*
   @param {Function} func
@@ -206,6 +235,11 @@ export function hasListeners(obj: object, eventName: string): boolean {
   @public
 */
 export function on<T extends AnyFn>(...args: [...eventNames: string[], func: T]): T {
+  deprecateUntil(
+    'The `on()` event decorator is deprecated. Use native JavaScript events or a dedicated event library instead.',
+    DEPRECATIONS.DEPRECATE_EVENTED
+  );
+
   let func = args.pop();
   let events = args as string[];
 
diff --git a/packages/@ember/-internals/metal/lib/observer.ts b/packages/@ember/-internals/metal/lib/observer.ts
index f1f8035fdbe..0cabeb7532b 100644
--- a/packages/@ember/-internals/metal/lib/observer.ts
+++ b/packages/@ember/-internals/metal/lib/observer.ts
@@ -43,7 +43,14 @@ export function addObserver(
 ): void {
   let eventName = changeEvent(path);
 
-  addListener(obj, eventName, target, method, false, sync);
+  addListener(
+    obj,
+    eventName,
+    target as any,
+    method as PropertyKey | ((...args: any[]) => void),
+    false,
+    sync
+  );
 
   let meta = peekMeta(obj);
 
@@ -77,7 +84,7 @@ export function removeObserver(
     deactivateObserver(obj, eventName, sync);
   }
 
-  removeListener(obj, eventName, target, method);
+  removeListener(obj, eventName, target as any, method as string | ((...args: any[]) => void));
 }
 
 function getOrCreateActiveObserversFor(target: object, sync: boolean) {
diff --git a/packages/@ember/-internals/metal/tests/computed_test.js b/packages/@ember/-internals/metal/tests/computed_test.js
index 516da6905f6..1a20fc2166c 100644
--- a/packages/@ember/-internals/metal/tests/computed_test.js
+++ b/packages/@ember/-internals/metal/tests/computed_test.js
@@ -984,16 +984,16 @@ moduleFor(
 class LazyObject {
   value = 123;
 
+  /* eslint-disable no-dupe-class-members */
   @computed('_value')
-  // eslint-disable-next-line no-dupe-class-members
   get value() {
     return get(this, '_value');
   }
 
-  // eslint-disable-next-line no-dupe-class-members
   set value(value) {
     set(this, '_value', value);
   }
+  /* eslint-enable no-dupe-class-members */
 
   static create() {
     obj = new LazyObject();
diff --git a/packages/@ember/-internals/metal/tests/events_test.js b/packages/@ember/-internals/metal/tests/events_test.js
index 109792c39b7..c50f3e83bd3 100644
--- a/packages/@ember/-internals/metal/tests/events_test.js
+++ b/packages/@ember/-internals/metal/tests/events_test.js
@@ -1,6 +1,7 @@
 import { on, addListener, removeListener, sendEvent, hasListeners } from '..';
 import Mixin from '@ember/object/mixin';
-import { moduleFor, AbstractTestCase } from 'internal-test-helpers';
+import { moduleFor, AbstractTestCase, expectDeprecation, testUnless } from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../deprecations';
 
 moduleFor(
   'system/props/events_test',
@@ -139,17 +140,26 @@ moduleFor(
       assert.equal(hasListeners(obj, 'event!'), true, 'has listeners');
     }
 
-    ['@test a listener can be added as part of a mixin'](assert) {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener can be added as part of a mixin`](assert) {
       let triggered = 0;
-      let MyMixin = Mixin.create({
-        foo1: on('bar', function () {
-          triggered++;
-        }),
-
-        foo2: on('bar', function () {
-          triggered++;
-        }),
-      });
+      let MyMixin;
+      expectDeprecation(
+        () => {
+          MyMixin = Mixin.create({
+            foo1: on('bar', function () {
+              triggered++;
+            }),
+
+            foo2: on('bar', function () {
+              triggered++;
+            }),
+          });
+        },
+        /`on\(\)` event decorator is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       let obj = {};
       MyMixin.apply(obj);
@@ -158,32 +168,63 @@ moduleFor(
       assert.equal(triggered, 2, 'should invoke listeners');
     }
 
-    [`@test 'on' asserts for invalid arguments`]() {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test 'on' asserts for invalid arguments`]() {
       expectAssertion(() => {
-        Mixin.create({
-          foo1: on('bar'),
-        });
+        expectDeprecation(
+          () => {
+            Mixin.create({
+              foo1: on('bar'),
+            });
+          },
+          /`on\(\)` event decorator is deprecated/,
+          DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+        );
       }, 'on expects function as last argument');
 
       expectAssertion(() => {
-        Mixin.create({
-          foo1: on(function () {}),
-        });
+        expectDeprecation(
+          () => {
+            Mixin.create({
+              foo1: on(function () {}),
+            });
+          },
+          /`on\(\)` event decorator is deprecated/,
+          DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+        );
       }, 'on called without valid event names');
     }
 
-    ['@test a listener added as part of a mixin may be overridden'](assert) {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener added as part of a mixin may be overridden`](assert) {
       let triggered = 0;
-      let FirstMixin = Mixin.create({
-        foo: on('bar', function () {
-          triggered++;
-        }),
-      });
-      let SecondMixin = Mixin.create({
-        foo: on('baz', function () {
-          triggered++;
-        }),
-      });
+      let FirstMixin;
+      expectDeprecation(
+        () => {
+          FirstMixin = Mixin.create({
+            foo: on('bar', function () {
+              triggered++;
+            }),
+          });
+        },
+        /`on\(\)` event decorator is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      let SecondMixin;
+      expectDeprecation(
+        () => {
+          SecondMixin = Mixin.create({
+            foo: on('baz', function () {
+              triggered++;
+            }),
+          });
+        },
+        /`on\(\)` event decorator is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       let obj = {};
       FirstMixin.apply(obj);
diff --git a/packages/@ember/-internals/utils/index.ts b/packages/@ember/-internals/utils/index.ts
index 329a6f7e793..2e310ef344d 100644
--- a/packages/@ember/-internals/utils/index.ts
+++ b/packages/@ember/-internals/utils/index.ts
@@ -33,3 +33,9 @@ export {
   teardownMandatorySetter,
   setWithMandatorySetter,
 } from './lib/mandatory-setter';
+export {
+  DEPRECATION,
+  setDeprecation,
+  findDeprecation,
+  disableDeprecations,
+} from './lib/mixin-deprecation';
diff --git a/packages/@ember/-internals/utils/lib/mixin-deprecation.ts b/packages/@ember/-internals/utils/lib/mixin-deprecation.ts
new file mode 100644
index 00000000000..373e5181940
--- /dev/null
+++ b/packages/@ember/-internals/utils/lib/mixin-deprecation.ts
@@ -0,0 +1,44 @@
+import type { DeprecationObject } from '@ember/-internals/deprecations';
+import type Mixin from '@ember/object/mixin';
+
+/** @internal */
+export const DEPRECATION = Symbol('DEPRECATION');
+
+/** @internal */
+export function setDeprecation(
+  mixin: Mixin,
+  value: { message: string; deprecation: DeprecationObject } | null
+) {
+  // SAFETY: Using symbol as index on Mixin - this is internal deprecated API tooling
+  (mixin as any)[DEPRECATION] = value;
+}
+
+let deprecationsEnabled = true;
+
+export function findDeprecation(
+  mixin: Mixin
+): { message: string; deprecation: DeprecationObject } | null {
+  if (!deprecationsEnabled) {
+    return null;
+  }
+  // SAFETY: Using symbol as index on Mixin - this is internal deprecated API tooling
+  if ((mixin as any)[DEPRECATION]) {
+    return (mixin as any)[DEPRECATION];
+  }
+  for (let childMixin of mixin.mixins ?? []) {
+    let deprecation = findDeprecation(childMixin);
+    if (deprecation) {
+      return deprecation;
+    }
+  }
+  return null;
+}
+
+export function disableDeprecations<T>(callback: () => T): T {
+  try {
+    deprecationsEnabled = false;
+    return callback();
+  } finally {
+    deprecationsEnabled = true;
+  }
+}
diff --git a/packages/@ember/-internals/views/index.ts b/packages/@ember/-internals/views/index.ts
index a84d01a080b..43c1afd840c 100644
--- a/packages/@ember/-internals/views/index.ts
+++ b/packages/@ember/-internals/views/index.ts
@@ -18,6 +18,7 @@ export {
 export { default as EventDispatcher } from './lib/system/event_dispatcher';
 export { default as ComponentLookup } from './lib/component_lookup';
 export { default as CoreView } from './lib/views/core_view';
+export { sendCoreViewEvent, hasCoreViewListener } from './lib/views/core-view-utils';
 export { default as ActionSupport } from './lib/mixins/action_support';
 export { MUTABLE_CELL } from './lib/compat/attrs';
 export { default as ViewStates } from './lib/views/states';
diff --git a/packages/@ember/-internals/views/lib/views/core-view-utils.ts b/packages/@ember/-internals/views/lib/views/core-view-utils.ts
new file mode 100644
index 00000000000..5de7023627a
--- /dev/null
+++ b/packages/@ember/-internals/views/lib/views/core-view-utils.ts
@@ -0,0 +1,14 @@
+import { hasListeners, sendEvent } from '@ember/-internals/metal';
+import type CoreView from './core_view';
+
+export function sendCoreViewEvent(view: CoreView, name: string, args: any[] = []) {
+  sendEvent(view, name, args);
+  let method = (view as any)[name];
+  if (typeof method === 'function') {
+    return method.apply(view, args);
+  }
+}
+
+export function hasCoreViewListener(view: CoreView, name: string) {
+  return typeof (view as any)[name] === 'function' || hasListeners(view, name);
+}
diff --git a/packages/@ember/-internals/views/lib/views/core_view.ts b/packages/@ember/-internals/views/lib/views/core_view.ts
index 241b233da65..8b0fa45f8d5 100644
--- a/packages/@ember/-internals/views/lib/views/core_view.ts
+++ b/packages/@ember/-internals/views/lib/views/core_view.ts
@@ -1,10 +1,11 @@
 import type { Renderer, View } from '@ember/-internals/glimmer';
 import { inject } from '@ember/-internals/metal';
 import { ActionHandler } from '@ember/-internals/runtime';
-import Evented from '@ember/object/evented';
 import { FrameworkObject } from '@ember/object/-internals';
 import type { ViewState } from './states';
 import states from './states';
+import Evented from '@ember/object/evented';
+import { disableDeprecations } from '@ember/-internals/utils';
 
 /**
   `CoreView` is an abstract class that exists to give view-like behavior
@@ -24,7 +25,7 @@ import states from './states';
 */
 
 interface CoreView extends Evented, ActionHandler, View {}
-class CoreView extends FrameworkObject.extend(Evented, ActionHandler) {
+class CoreView extends disableDeprecations(() => FrameworkObject.extend(Evented, ActionHandler)) {
   isView = true;
 
   declare _states: typeof states;
diff --git a/packages/@ember/-internals/views/lib/views/states.ts b/packages/@ember/-internals/views/lib/views/states.ts
index c9480ffbdf4..1bdf1a1df98 100644
--- a/packages/@ember/-internals/views/lib/views/states.ts
+++ b/packages/@ember/-internals/views/lib/views/states.ts
@@ -4,6 +4,7 @@ import { assert } from '@ember/debug';
 import { flaggedInstrument } from '@ember/instrumentation';
 import { join } from '@ember/runloop';
 import { DEBUG } from '@glimmer/env';
+import { hasCoreViewListener, sendCoreViewEvent } from './core-view-utils';
 
 export interface ViewState {
   enter?(view: Component): void;
@@ -45,11 +46,13 @@ const HAS_ELEMENT: Readonly<ViewState> = Object.freeze({
 
   // Handle events from `Ember.EventDispatcher`
   handleEvent(view: Component, eventName: string, event: Event) {
-    if (view.has(eventName)) {
+    if (hasCoreViewListener(view, eventName)) {
       // Handler should be able to re-dispatch events, so we don't
       // preventDefault or stopPropagation.
       return flaggedInstrument(`interaction.${eventName}`, { event, view }, () => {
-        return join(view, view.trigger, eventName, event);
+        return join(() => {
+          return sendCoreViewEvent(view, eventName, [event]);
+        });
       });
     } else {
       return true; // continue event propagation
diff --git a/packages/@ember/object/evented.ts b/packages/@ember/object/evented.ts
index 2134d344206..83be072e82f 100644
--- a/packages/@ember/object/evented.ts
+++ b/packages/@ember/object/evented.ts
@@ -1,4 +1,6 @@
 import { addListener, removeListener, hasListeners, sendEvent } from '@ember/-internals/metal';
+import { DEPRECATIONS, deprecateUntil } from '@ember/-internals/deprecations';
+import { setDeprecation } from '@ember/-internals/utils';
 import Mixin from '@ember/object/mixin';
 
 export { on } from '@ember/-internals/metal';
@@ -46,6 +48,7 @@ export { on } from '@ember/-internals/metal';
 
   @class Evented
   @public
+  @deprecated Use native JavaScript events or a dedicated event library instead.
  */
 interface Evented {
   /**
@@ -63,6 +66,7 @@ interface Evented {
     parameter is used the callback method becomes the third argument.
 
     @method on
+    @deprecated Use native JavaScript events or a dedicated event library instead.
     @param {String} name The name of the event
     @param {Object} [target] The "this" binding for the callback
     @param {Function|String} method A function or the name of a function to be called on `target`
@@ -85,6 +89,7 @@ interface Evented {
     becomes the third argument.
 
     @method one
+    @deprecated Use native JavaScript events or a dedicated event library instead.
     @param {String} name The name of the event
     @param {Object} [target] The "this" binding for the callback
     @param {Function|String} method A function or the name of a function to be called on `target`
@@ -113,6 +118,7 @@ interface Evented {
     ```
 
     @method trigger
+    @deprecated Use native JavaScript events or a dedicated event library instead.
     @param {String} name The name of the event
     @param {Object...} args Optional arguments to pass on
     @public
@@ -122,6 +128,7 @@ interface Evented {
     Cancels subscription for given name, target, and method.
 
     @method off
+    @deprecated Use native JavaScript events or a dedicated event library instead.
     @param {String} name The name of the event
     @param {Object} target The target of the subscription
     @param {Function|String} method The function or the name of a function of the subscription
@@ -138,6 +145,7 @@ interface Evented {
     Checks to see if object has any subscriptions for named event.
 
     @method has
+    @deprecated Use native JavaScript events or a dedicated event library instead.
     @param {String} name The name of the event
     @return {Boolean} does the object have a subscription for event
     @public
@@ -146,27 +154,56 @@ interface Evented {
 }
 const Evented = Mixin.create({
   on(name: string, target: object, method?: string | Function) {
-    addListener(this, name, target, method);
+    deprecateUntil(
+      '`Evented#on` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+      DEPRECATIONS.DEPRECATE_EVENTED
+    );
+    // SAFETY: The types are not actually correct, but it's not worth the effort to fix them, since we're deprecating this API.
+    addListener(this, name, target, method as PropertyKey | ((...args: any[]) => void));
     return this;
   },
 
   one(name: string, target: object, method?: string | Function) {
-    addListener(this, name, target, method, true);
+    deprecateUntil(
+      '`Evented#one` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+      DEPRECATIONS.DEPRECATE_EVENTED
+    );
+    // SAFETY: The types are not actually correct, but it's not worth the effort to fix them, since we're deprecating this API.
+    addListener(this, name, target, method as PropertyKey | ((...args: any[]) => void), true);
     return this;
   },
 
   trigger(name: string, ...args: any[]) {
+    deprecateUntil(
+      '`Evented#trigger` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+      DEPRECATIONS.DEPRECATE_EVENTED
+    );
     sendEvent(this, name, args);
   },
 
   off(name: string, target: object, method?: string | Function) {
-    removeListener(this, name, target, method);
+    deprecateUntil(
+      '`Evented#off` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+      DEPRECATIONS.DEPRECATE_EVENTED
+    );
+    // SAFETY: The types are not actually correct, but it's not worth the effort to fix them, since we're deprecating this API.
+    removeListener(this, name, target, method as string | ((...args: any[]) => void));
     return this;
   },
 
   has(name: string) {
+    deprecateUntil(
+      '`Evented#has` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+      DEPRECATIONS.DEPRECATE_EVENTED
+    );
     return hasListeners(this, name);
   },
 });
 
+setDeprecation(Evented, {
+  message:
+    'Evented is deprecated. Use native JavaScript events or a dedicated event library instead.',
+  deprecation: DEPRECATIONS.DEPRECATE_EVENTED,
+});
+
 export default Evented;
diff --git a/packages/@ember/object/events.ts b/packages/@ember/object/events.ts
index 3f4559266fc..af1230fbc07 100644
--- a/packages/@ember/object/events.ts
+++ b/packages/@ember/object/events.ts
@@ -1 +1,78 @@
-export { addListener, removeListener, sendEvent } from '@ember/-internals/metal';
+import {
+  addListener as originalAddListener,
+  removeListener as originalRemoveListener,
+  sendEvent as originalSendEvent,
+} from '@ember/-internals/metal';
+import { DEPRECATIONS, deprecateUntil } from '@ember/-internals/deprecations';
+
+export function addListener<Target>(
+  obj: object,
+  eventName: string,
+  target: Target,
+  method: PropertyKey | ((this: Target, ...args: any[]) => void),
+  once?: boolean,
+  sync?: boolean
+): void;
+export function addListener(
+  obj: object,
+  eventName: string,
+  method: PropertyKey | ((...args: any[]) => void)
+): void;
+export function addListener(
+  obj: object,
+  eventName: string,
+  target: object | PropertyKey | ((...args: any[]) => void) | null,
+  method?: PropertyKey | ((...args: any[]) => void),
+  once?: boolean,
+  sync?: boolean
+): void {
+  deprecateUntil(
+    'Importing `addListener` from `@ember/object/events` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+    DEPRECATIONS.DEPRECATE_EVENTED
+  );
+  return originalAddListener(
+    obj,
+    eventName,
+    target as any,
+    method as PropertyKey | ((...args: any[]) => void),
+    once,
+    sync
+  );
+}
+
+export function removeListener<Target>(
+  obj: object,
+  eventName: string,
+  target: Target,
+  method: PropertyKey | ((this: Target, ...args: any[]) => void)
+): void;
+export function removeListener(
+  obj: object,
+  eventName: string,
+  method: PropertyKey | ((...args: any[]) => void)
+): void;
+export function removeListener(
+  obj: object,
+  eventName: string,
+  target: object | PropertyKey | ((...args: any[]) => void) | null,
+  method?: PropertyKey | ((...args: any[]) => void)
+): void {
+  deprecateUntil(
+    'Importing `removeListener` from `@ember/object/events` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+    DEPRECATIONS.DEPRECATE_EVENTED
+  );
+  return originalRemoveListener(
+    obj,
+    eventName,
+    target as any,
+    method as string | ((...args: any[]) => void)
+  );
+}
+
+export const sendEvent = (...args: Parameters<typeof originalSendEvent>) => {
+  deprecateUntil(
+    'Importing `sendEvent` from `@ember/object/events` is deprecated. Use native JavaScript events or a dedicated event library instead.',
+    DEPRECATIONS.DEPRECATE_EVENTED
+  );
+  return originalSendEvent(...args);
+};
diff --git a/packages/@ember/object/mixin.ts b/packages/@ember/object/mixin.ts
index 32b550c2cf9..77e88ce0137 100644
--- a/packages/@ember/object/mixin.ts
+++ b/packages/@ember/object/mixin.ts
@@ -4,8 +4,16 @@
 import { INIT_FACTORY } from '@ember/-internals/container';
 import type { Meta } from '@ember/-internals/meta';
 import { meta as metaFor, peekMeta } from '@ember/-internals/meta';
-import { guidFor, observerListenerMetaFor, ROOT, wrap } from '@ember/-internals/utils';
+import {
+  guidFor,
+  observerListenerMetaFor,
+  ROOT,
+  wrap,
+  DEPRECATION,
+  findDeprecation,
+} from '@ember/-internals/utils';
 import { assert } from '@ember/debug';
+import { deprecateUntil, type DeprecationObject } from '@ember/-internals/deprecations';
 import { DEBUG } from '@glimmer/env';
 import {
   type ComputedDecorator,
@@ -14,6 +22,8 @@ import {
   type ComputedPropertySetter,
   type ComputedDescriptor,
   isClassicDecorator,
+  addListener,
+  removeListener,
 } from '@ember/-internals/metal';
 import {
   ComputedProperty,
@@ -27,7 +37,6 @@ import {
   defineDecorator,
   defineValue,
 } from '@ember/-internals/metal';
-import { addListener, removeListener } from '@ember/object/events';
 
 const a_concat = Array.prototype.concat;
 const { isArray } = Array;
@@ -385,10 +394,12 @@ function updateObserversAndListeners(obj: object, key: string, fn: Function, add
   }
 
   if (listeners !== undefined) {
-    let updateListener = add ? addListener : removeListener;
-
     for (let listener of listeners) {
-      updateListener(obj, listener, null, key);
+      if (add) {
+        addListener(obj, listener, null, key as PropertyKey);
+      } else {
+        removeListener(obj, listener, null, key);
+      }
     }
   }
 }
@@ -543,6 +554,9 @@ export default class Mixin {
   /** @internal */
   properties: { [key: string]: any } | undefined;
 
+  /** @internal */
+  [DEPRECATION]: { message: string; deprecation: DeprecationObject } | null = null;
+
   /** @internal */
   ownerConstructor: any;
 
@@ -621,6 +635,15 @@ export default class Mixin {
       return this;
     }
 
+    if (DEBUG) {
+      for (let mixin of args) {
+        let dep = mixin instanceof Mixin ? findDeprecation(mixin) : null;
+        if (dep) {
+          deprecateUntil(dep.message, dep.deprecation);
+        }
+      }
+    }
+
     if (this.properties) {
       let currentMixin = new Mixin(undefined, this.properties);
       this.properties = undefined;
diff --git a/packages/@ember/object/tests/es-compatibility-test.js b/packages/@ember/object/tests/es-compatibility-test.js
index 33cff30a067..35372ca5f70 100644
--- a/packages/@ember/object/tests/es-compatibility-test.js
+++ b/packages/@ember/object/tests/es-compatibility-test.js
@@ -9,7 +9,14 @@ import {
   sendEvent,
 } from '@ember/-internals/metal';
 import Mixin from '@ember/object/mixin';
-import { moduleFor, AbstractTestCase, runLoopSettled } from 'internal-test-helpers';
+import {
+  moduleFor,
+  AbstractTestCase,
+  runLoopSettled,
+  expectDeprecation,
+  testUnless,
+} from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../-internals/deprecations';
 
 moduleFor(
   'EmberObject ES Compatibility',
@@ -276,37 +283,48 @@ moduleFor(
       SubEmberObject.metaForProperty('foo');
     }
 
-    '@test observes / removeObserver on / removeListener interop'(assert) {
+    [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test observes / removeObserver on / removeListener interop`](
+      assert
+    ) {
       let fooDidChangeBase = 0;
       let fooDidChangeA = 0;
       let fooDidChangeB = 0;
       let someEventBase = 0;
       let someEventA = 0;
       let someEventB = 0;
-      class A extends EmberObject.extend({
-        fooDidChange: observer('foo', function () {
-          fooDidChangeBase++;
-        }),
-
-        onSomeEvent: on('someEvent', function () {
-          someEventBase++;
-        }),
-      }) {
-        init() {
-          super.init();
-          this.foo = 'bar';
-        }
-
-        fooDidChange() {
-          super.fooDidChange();
-          fooDidChangeA++;
-        }
-
-        onSomeEvent() {
-          super.onSomeEvent();
-          someEventA++;
-        }
-      }
+      let A;
+      expectDeprecation(
+        () => {
+          A = class extends (
+            EmberObject.extend({
+              fooDidChange: observer('foo', function () {
+                fooDidChangeBase++;
+              }),
+
+              onSomeEvent: on('someEvent', function () {
+                someEventBase++;
+              }),
+            })
+          ) {
+            init() {
+              super.init();
+              this.foo = 'bar';
+            }
+
+            fooDidChange() {
+              super.fooDidChange();
+              fooDidChangeA++;
+            }
+
+            onSomeEvent() {
+              super.onSomeEvent();
+              someEventA++;
+            }
+          };
+        },
+        /`on\(\)` event decorator is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       class B extends A {
         fooDidChange() {
diff --git a/packages/@ember/object/tests/evented_test.js b/packages/@ember/object/tests/evented_test.js
index 03c65149b8a..2e7a920252d 100644
--- a/packages/@ember/object/tests/evented_test.js
+++ b/packages/@ember/object/tests/evented_test.js
@@ -1,21 +1,44 @@
 import CoreObject from '@ember/object/core';
 import EventedMixin from '@ember/object/evented';
-import { moduleFor, AbstractTestCase } from 'internal-test-helpers';
+import { moduleFor, AbstractTestCase, expectDeprecation, testUnless } from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../-internals/deprecations';
 
 moduleFor(
   'Ember.Evented',
   class extends AbstractTestCase {
-    ['@test works properly on proxy-ish objects'](assert) {
-      let eventedProxyObj = class extends CoreObject.extend(EventedMixin) {
-        unknownProperty() {
-          return true;
-        }
-      }.create();
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test works properly on proxy-ish objects`](assert) {
+      let eventedProxyObj;
+      expectDeprecation(
+        () => {
+          eventedProxyObj = class extends CoreObject.extend(EventedMixin) {
+            unknownProperty() {
+              return true;
+            }
+          }.create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       let noop = function () {};
 
-      eventedProxyObj.on('foo', noop);
-      eventedProxyObj.off('foo', noop);
+      expectDeprecation(
+        () => {
+          eventedProxyObj.on('foo', noop);
+        },
+        /Evented#on` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          eventedProxyObj.off('foo', noop);
+        },
+        /Evented#off` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.ok(true, 'An assertion was triggered');
     }
diff --git a/packages/@ember/object/tests/events_test.js b/packages/@ember/object/tests/events_test.js
index fee30bd5bdb..c3daddf6c3d 100644
--- a/packages/@ember/object/tests/events_test.js
+++ b/packages/@ember/object/tests/events_test.js
@@ -1,29 +1,59 @@
 import EmberObject from '@ember/object';
 import Evented from '@ember/object/evented';
-import { moduleFor, AbstractTestCase } from 'internal-test-helpers';
+import { moduleFor, AbstractTestCase, expectDeprecation, testUnless } from 'internal-test-helpers';
+import { DEPRECATIONS } from '../../-internals/deprecations';
 
 moduleFor(
   'Object events',
   class extends AbstractTestCase {
-    ['@test a listener can be added to an object'](assert) {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener can be added to an object`](assert) {
       let count = 0;
       let F = function () {
         count++;
       };
 
-      let obj = EmberObject.extend(Evented).create();
-
-      obj.on('event!', F);
-      obj.trigger('event!');
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.on('event!', F);
+        },
+        /Evented#on` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+      expectDeprecation(
+        () => {
+          obj.trigger('event!');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.equal(count, 1, 'the event was triggered');
 
-      obj.trigger('event!');
+      expectDeprecation(
+        () => {
+          obj.trigger('event!');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.equal(count, 2, 'the event was triggered');
     }
 
-    ['@test a listener can be added and removed automatically the first time it is triggered'](
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener can be added and removed automatically the first time it is triggered`](
       assert
     ) {
       let count = 0;
@@ -31,77 +61,174 @@ moduleFor(
         count++;
       };
 
-      let obj = EmberObject.extend(Evented).create();
-
-      obj.one('event!', F);
-      obj.trigger('event!');
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.one('event!', F);
+        },
+        /Evented#one` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.trigger('event!');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.equal(count, 1, 'the event was triggered');
 
-      obj.trigger('event!');
+      expectDeprecation(
+        () => {
+          obj.trigger('event!');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.equal(count, 1, 'the event was not triggered again');
     }
 
-    ['@test triggering an event can have arguments'](assert) {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test triggering an event can have arguments`](assert) {
       let self, args;
 
-      let obj = EmberObject.extend(Evented).create();
-
-      obj.on('event!', function () {
-        args = [].slice.call(arguments);
-        self = this;
-      });
-
-      obj.trigger('event!', 'foo', 'bar');
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.on('event!', function () {
+            args = [].slice.call(arguments);
+            self = this;
+          });
+        },
+        /Evented#on` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.trigger('event!', 'foo', 'bar');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.deepEqual(args, ['foo', 'bar']);
       assert.equal(self, obj);
     }
 
-    ['@test a listener can be added and removed automatically and have arguments'](assert) {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener can be added and removed automatically and have arguments`](assert) {
       let self, args;
       let count = 0;
 
-      let obj = EmberObject.extend(Evented).create();
-
-      obj.one('event!', function () {
-        args = [].slice.call(arguments);
-        self = this;
-        count++;
-      });
-
-      obj.trigger('event!', 'foo', 'bar');
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.one('event!', function () {
+            args = [].slice.call(arguments);
+            self = this;
+            count++;
+          });
+        },
+        /Evented#one` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.trigger('event!', 'foo', 'bar');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.deepEqual(args, ['foo', 'bar']);
       assert.equal(self, obj);
       assert.equal(count, 1, 'the event is triggered once');
 
-      obj.trigger('event!', 'baz', 'bat');
+      expectDeprecation(
+        () => {
+          obj.trigger('event!', 'baz', 'bat');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.deepEqual(args, ['foo', 'bar']);
       assert.equal(count, 1, 'the event was not triggered again');
       assert.equal(self, obj);
     }
 
-    ['@test binding an event can specify a different target'](assert) {
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test binding an event can specify a different target`](assert) {
       let self, args;
 
-      let obj = EmberObject.extend(Evented).create();
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
       let target = {};
 
-      obj.on('event!', target, function () {
-        args = [].slice.call(arguments);
-        self = this;
-      });
-
-      obj.trigger('event!', 'foo', 'bar');
+      expectDeprecation(
+        () => {
+          obj.on('event!', target, function () {
+            args = [].slice.call(arguments);
+            self = this;
+          });
+        },
+        /Evented#on` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.trigger('event!', 'foo', 'bar');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.deepEqual(args, ['foo', 'bar']);
       assert.equal(self, target);
     }
 
-    ['@test a listener registered with one can take method as string and can be added with different target'](
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener registered with one can take method as string and can be added with different target`](
       assert
     ) {
       let count = 0;
@@ -110,46 +237,152 @@ moduleFor(
         count++;
       };
 
-      let obj = EmberObject.extend(Evented).create();
-
-      obj.one('event!', target, 'fn');
-      obj.trigger('event!');
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.one('event!', target, 'fn');
+        },
+        /Evented#one` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.trigger('event!');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.equal(count, 1, 'the event was triggered');
 
-      obj.trigger('event!');
+      expectDeprecation(
+        () => {
+          obj.trigger('event!');
+        },
+        /Evented#trigger` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
 
       assert.equal(count, 1, 'the event was not triggered again');
     }
 
-    ['@test a listener registered with one can be removed with off'](assert) {
-      let obj = class extends EmberObject.extend(Evented) {
-        F() {}
-      }.create();
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test a listener registered with one can be removed with off`](assert) {
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = class extends EmberObject.extend(Evented) {
+            F() {}
+          }.create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
       let F = function () {};
 
-      obj.one('event!', F);
-      obj.one('event!', obj, 'F');
-
-      assert.equal(obj.has('event!'), true, 'has events');
-
-      obj.off('event!', F);
-      obj.off('event!', obj, 'F');
-
-      assert.equal(obj.has('event!'), false, 'has no more events');
+      expectDeprecation(
+        () => {
+          obj.one('event!', F);
+        },
+        /Evented#one` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.one('event!', obj, 'F');
+        },
+        /Evented#one` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      let objHas;
+      expectDeprecation(
+        () => {
+          objHas = obj.has('event!');
+        },
+        /Evented#has` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+      assert.equal(objHas, true, 'has events');
+
+      expectDeprecation(
+        () => {
+          obj.off('event!', F);
+        },
+        /Evented#off` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          obj.off('event!', obj, 'F');
+        },
+        /Evented#off` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      expectDeprecation(
+        () => {
+          objHas = obj.has('event!');
+        },
+        /Evented#has` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
+
+      assert.equal(objHas, false, 'has no more events');
     }
 
-    ['@test adding and removing listeners should be chainable'](assert) {
-      let obj = EmberObject.extend(Evented).create();
+    [`${testUnless(
+      DEPRECATIONS.DEPRECATE_EVENTED.isRemoved
+    )} @test adding and removing listeners should be chainable`](assert) {
+      let obj;
+      expectDeprecation(
+        () => {
+          obj = EmberObject.extend(Evented).create();
+        },
+        /Evented is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
       let F = function () {};
 
-      let ret = obj.on('event!', F);
+      let ret;
+
+      expectDeprecation(
+        () => {
+          ret = obj.on('event!', F);
+        },
+        /Evented#on` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
       assert.equal(ret, obj, '#on returns self');
 
-      ret = obj.off('event!', F);
+      expectDeprecation(
+        () => {
+          ret = obj.off('event!', F);
+        },
+        /Evented#off` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
       assert.equal(ret, obj, '#off returns self');
 
-      ret = obj.one('event!', F);
+      expectDeprecation(
+        () => {
+          ret = obj.one('event!', F);
+        },
+        /Evented#one` is deprecated/,
+        DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+      );
       assert.equal(ret, obj, '#one returns self');
     }
   }
diff --git a/packages/@ember/routing/route.ts b/packages/@ember/routing/route.ts
index 7b4a8f24eac..066eb847101 100644
--- a/packages/@ember/routing/route.ts
+++ b/packages/@ember/routing/route.ts
@@ -4,6 +4,7 @@ import {
   defineProperty,
   descriptorForProperty,
   flushAsyncObservers,
+  sendEvent,
 } from '@ember/-internals/metal';
 import type Owner from '@ember/owner';
 import { getOwner } from '@ember/-internals/owner';
@@ -36,6 +37,7 @@ import {
   prefixRouteNameArg,
   stashParamNames,
 } from './lib/utils';
+import { disableDeprecations } from '@ember/-internals/utils';
 
 export interface ExtendedInternalRouteInfo<R extends Route> extends InternalRouteInfo<R> {
   _names?: unknown[];
@@ -252,7 +254,10 @@ interface Route<Model = unknown> extends IRoute<Model>, ActionHandler, Evented {
   error?(error: Error, transition: Transition): boolean | void;
 }
 
-class Route<Model = unknown> extends EmberObject.extend(ActionHandler, Evented) implements IRoute {
+class Route<Model = unknown>
+  extends disableDeprecations(() => EmberObject.extend(ActionHandler, Evented))
+  implements IRoute
+{
   static isRouteFactory = true;
 
   // These properties will end up appearing in the public interface because we
@@ -769,7 +774,7 @@ class Route<Model = unknown> extends EmberObject.extend(ActionHandler, Evented)
   */
   exit(transition?: Transition) {
     this.deactivate(transition);
-    this.trigger('deactivate', transition);
+    sendEvent(this, 'deactivate', [transition]);
     this.teardownViews();
   }
 
@@ -795,7 +800,7 @@ class Route<Model = unknown> extends EmberObject.extend(ActionHandler, Evented)
   enter(transition: Transition) {
     this[RENDER_STATE] = undefined;
     this.activate(transition);
-    this.trigger('activate', transition);
+    sendEvent(this, 'activate', [transition]);
   }
 
   /**
diff --git a/packages/@ember/routing/router-service.ts b/packages/@ember/routing/router-service.ts
index 936e7539d1c..053c77af4bc 100644
--- a/packages/@ember/routing/router-service.ts
+++ b/packages/@ember/routing/router-service.ts
@@ -2,7 +2,6 @@
  * @module @ember/routing/router-service
  */
 import { getOwner } from '@ember/-internals/owner';
-import Evented from '@ember/object/evented';
 import { assert } from '@ember/debug';
 import { readOnly } from '@ember/object/computed';
 import Service from '@ember/service';
@@ -13,6 +12,7 @@ import EmberRouter from '@ember/routing/router';
 import type { RouteInfo, RouteInfoWithAttributes } from './lib/route-info';
 import type { RouteArgs, RouteOptions } from './lib/utils';
 import { extractRouteArgs, resemblesURL, shallowEqual } from './lib/utils';
+import { addListener, hasListeners, removeListener, sendEvent } from '@ember/-internals/metal';
 
 export const ROUTER = Symbol('ROUTER');
 
@@ -24,6 +24,8 @@ function cleanURL(url: string, rootURL: string) {
   return url.substring(rootURL.length);
 }
 
+type EventName = 'routeWillChange' | 'routeDidChange';
+
 /**
    The Router service is the public API that provides access to the router.
 
@@ -55,14 +57,108 @@ function cleanURL(url: string, rootURL: string) {
    @extends Service
    @class RouterService
  */
-interface RouterService extends Evented {
+class RouterService extends Service {
+  [ROUTER]?: EmberRouter;
+
+  /**
+    Subscribes to a named event with given function.
+
+    @method on
+    @param {String} name The name of the event
+    @param {Object} [target] The "this" binding for the callback
+    @param {Function|String} method A function or the name of a function to be called on `target`
+    @return this
+  */
+  on(name: 'routeWillChange' | 'routeDidChange', callback: (transition: Transition) => void): this;
+  on<Target>(
+    name: EventName,
+    target: Target,
+    method: string | ((this: Target, ...args: any[]) => void)
+  ): this;
+  on(name: EventName, method: ((...args: any[]) => void) | string): this;
   on(
-    eventName: 'routeWillChange' | 'routeDidChange',
-    callback: (transition: Transition) => void
+    name: EventName,
+    target: object | ((...args: any[]) => void) | string,
+    method?: string | ((...args: any[]) => void)
+  ) {
+    // SAFETY: The types are not actually correct, but it's not worth the effort to fix them, since we'll be deprecating this API soon.
+    addListener(this, name, target, method as any);
+    return this;
+  }
+
+  /**
+    Subscribes a function to a named event and then cancels the subscription
+    after the first time the event is triggered.
+
+    @method one
+    @param {String} name The name of the event
+    @param {Object} [target] The "this" binding for the callback
+    @param {Function|String} method A function or the name of a function to be called on `target`
+    @return this
+  */
+  one<Target>(
+    name: string,
+    target: Target,
+    method: string | ((this: Target, ...args: any[]) => void)
   ): this;
-}
-class RouterService extends Service.extend(Evented) {
-  [ROUTER]?: EmberRouter;
+  one(name: string, method: string | ((...args: any[]) => void)): this;
+  one(
+    name: string,
+    target: object | string | ((...args: any[]) => void),
+    method?: string | Function
+  ) {
+    // SAFETY: The types are not actually correct, but it's not worth the effort to fix them, since we'll be deprecating this API soon.
+    addListener(this, name, target, method as any, true);
+    return this;
+  }
+
+  /**
+    Triggers a named event for the object.
+
+    @method trigger
+    @param {String} name The name of the event
+    @param {Object...} args Optional arguments to pass on
+    @return {boolean} true if listeners were notified, false otherwise
+  */
+  trigger(name: string, ...args: any[]): boolean {
+    return sendEvent(this, name, args);
+  }
+
+  /**
+    Cancels subscription for given name, target, and method.
+
+    @method off
+    @param {String} name The name of the event
+    @param {Object} target The target of the subscription
+    @param {Function|String} method The function or the name of a function of the subscription
+    @return this
+  */
+  off<Target>(
+    name: string,
+    target: Target,
+    method: string | ((this: Target, ...args: any[]) => void)
+  ): this;
+  off(name: string, method: string | ((...args: any[]) => void)): this;
+  off(
+    name: string,
+    target: object | string | ((...args: any[]) => void),
+    method?: string | Function
+  ) {
+    // SAFETY: The types are not actually correct, but it's not worth the effort to fix them, since we'll be deprecating this API soon.
+    removeListener(this, name, target as any, method as any);
+    return this;
+  }
+
+  /**
+    Checks to see if object has any subscriptions for named event.
+
+    @method has
+    @param {String} name The name of the event
+    @return {Boolean} does the object have a subscription for event
+   */
+  has(name: string) {
+    return hasListeners(this, name);
+  }
 
   get _router(): EmberRouter {
     let router = this[ROUTER];
diff --git a/packages/@ember/routing/router.ts b/packages/@ember/routing/router.ts
index a52b28f0a32..735fe11187d 100644
--- a/packages/@ember/routing/router.ts
+++ b/packages/@ember/routing/router.ts
@@ -50,6 +50,8 @@ import type { QueryParams } from 'route-recognizer';
 import type { AnyFn, MethodNamesOf, OmitFirst } from '@ember/-internals/utility-types';
 import type { Template } from '@glimmer/interfaces';
 import type ApplicationInstance from '@ember/application/instance';
+import { sendEvent } from '@ember/-internals/metal';
+import { disableDeprecations } from '@ember/-internals/utils';
 
 /**
 @module @ember/routing/router
@@ -135,7 +137,10 @@ const { slice } = Array.prototype;
   @uses Evented
   @public
 */
-class EmberRouter extends EmberObject.extend(Evented) implements Evented {
+class EmberRouter
+  extends disableDeprecations(() => EmberObject.extend(Evented))
+  implements Evented
+{
   /**
    Represents the URL of the root of the application, often '/'. This prefix is
     assumed on all routes defined on this router.
@@ -415,7 +420,7 @@ class EmberRouter extends EmberObject.extend(Evented) implements Evented {
       }
 
       routeWillChange(transition: Transition) {
-        router.trigger('routeWillChange', transition);
+        sendEvent(router, 'routeWillChange', [transition]);
 
         if (DEBUG) {
           freezeRouteInfo(transition);
@@ -433,7 +438,7 @@ class EmberRouter extends EmberObject.extend(Evented) implements Evented {
       routeDidChange(transition: Transition) {
         router.set('currentRoute', transition.to);
         once(() => {
-          router.trigger('routeDidChange', transition);
+          sendEvent(router, 'routeDidChange', [transition]);
 
           if (DEBUG) {
             freezeRouteInfo(transition);
diff --git a/packages/ember/barrel.ts b/packages/ember/barrel.ts
index 55b88a16432..afa6b18c8cf 100644
--- a/packages/ember/barrel.ts
+++ b/packages/ember/barrel.ts
@@ -520,17 +520,26 @@ namespace Ember {
   export declare let lookup: Record<string, unknown>;
 
   /**
-   This should not be needed.
-   You may be able to use an event listener for the error event on window.
-
-   `window.addEventListener('error', eventHandler);`
-
-   For promise rejections, you'll want to use the unhandledrejection event.
-   `window.addEventListener('unhandledrejection', eventHandler);`
-
-   If you really need the original behavior:
-
-   `import { getOnerror, setOnerror } from '@ember/-internals/error-handling';`
+    A function may be assigned to `Ember.onerror` to be called when Ember
+    internals encounter an error. This is useful for specialized error handling
+    and reporting code.
+
+    ```javascript
+
+    Ember.onerror = function(error) {
+      const payload = {
+        stack: error.stack,
+        otherInformation: 'whatever app state you want to provide'
+      };
+
+      fetch('/report-error', {
+        method: 'POST',
+        body: JSON.stringify(payload)
+      });
+    };
+    ```
+
+    Internally, `Ember.onerror` is used as Backburner's error handler.
 
     @event onerror
     @for Ember
diff --git a/packages/ember/tests/routing/decoupled_basic_test.js b/packages/ember/tests/routing/decoupled_basic_test.js
index a71b245d919..832517ec48e 100644
--- a/packages/ember/tests/routing/decoupled_basic_test.js
+++ b/packages/ember/tests/routing/decoupled_basic_test.js
@@ -13,7 +13,10 @@ import {
   ModuleBasedTestResolver,
   runDestroy,
   runTask,
+  expectDeprecation,
+  testUnless,
 } from 'internal-test-helpers';
+import { DEPRECATIONS } from '@ember/-internals/deprecations';
 import { run } from '@ember/runloop';
 import { addObserver } from '@ember/-internals/metal';
 import { service } from '@ember/service';
@@ -878,8 +881,10 @@ moduleFor(
       });
     }
 
-    ['@test `activate` event fires on the route'](assert) {
-      assert.expect(4);
+    [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test \`activate\` event fires on the route`](
+      assert
+    ) {
+      assert.expect(5);
 
       let eventFired = 0;
 
@@ -893,10 +898,16 @@ moduleFor(
           init() {
             super.init(...arguments);
 
-            this.on('activate', function (transition) {
-              assert.equal(++eventFired, 1, 'activate event is fired once');
-              assert.ok(transition, 'transition is passed to activate event');
-            });
+            expectDeprecation(
+              () => {
+                this.on('activate', function (transition) {
+                  assert.equal(++eventFired, 1, 'activate event is fired once');
+                  assert.ok(transition, 'transition is passed to activate event');
+                });
+              },
+              /Evented#on` is deprecated/,
+              DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+            );
           }
 
           activate(transition) {
@@ -909,8 +920,10 @@ moduleFor(
       return this.visit('/nork');
     }
 
-    ['@test `deactivate` event fires on the route'](assert) {
-      assert.expect(4);
+    [`${testUnless(DEPRECATIONS.DEPRECATE_EVENTED.isRemoved)} @test \`deactivate\` event fires on the route`](
+      assert
+    ) {
+      assert.expect(5);
 
       let eventFired = 0;
 
@@ -925,10 +938,16 @@ moduleFor(
           init() {
             super.init(...arguments);
 
-            this.on('deactivate', function (transition) {
-              assert.equal(++eventFired, 1, 'deactivate event is fired once');
-              assert.ok(transition, 'transition is passed');
-            });
+            expectDeprecation(
+              () => {
+                this.on('deactivate', function (transition) {
+                  assert.equal(++eventFired, 1, 'deactivate event is fired once');
+                  assert.ok(transition, 'transition is passed');
+                });
+              },
+              /Evented#on` is deprecated/,
+              DEPRECATIONS.DEPRECATE_EVENTED.isEnabled
+            );
           }
 
           deactivate(transition) {
diff --git a/type-tests/@ember/routing-test/router-service.ts b/type-tests/@ember/routing-test/router-service.ts
index 2b6083b8a34..0944a281c4e 100644
--- a/type-tests/@ember/routing-test/router-service.ts
+++ b/type-tests/@ember/routing-test/router-service.ts
@@ -22,7 +22,7 @@ expectTypeOf(router.on('routeWillChange', routeWillChangeHandler)).toEqualTypeOf
 expectTypeOf(router.has('routeWillChange')).toEqualTypeOf<boolean>();
 expectTypeOf(router.off('routeWillChange', routeWillChangeHandler)).toEqualTypeOf<RouterService>();
 expectTypeOf(router.one('routeWillChange', routeWillChangeHandler)).toEqualTypeOf<RouterService>();
-expectTypeOf(router.trigger('routeWillChange', 'boo')).toBeAny();
+expectTypeOf(router.trigger('routeWillChange', 'boo')).toEqualTypeOf<boolean>();
 
 const transition = router.transitionTo('someRoute');