diff --git a/packages/service-worker/src/index.ts b/packages/service-worker/src/index.ts
index bd89ce2ff2..a7defed04f 100644
--- a/packages/service-worker/src/index.ts
+++ b/packages/service-worker/src/index.ts
@@ -14,6 +14,7 @@
 * found in the LICENSE file at https://angular.io/license
 */
 
+export {UpdateActivatedEvent, UpdateAvailableEvent} from './low_level';
 export {ServiceWorkerModule} from './module';
 export {SwPush} from './push';
-export {SwUpdate} from './update';
\ No newline at end of file
+export {SwUpdate} from './update';
diff --git a/packages/service-worker/src/low_level.ts b/packages/service-worker/src/low_level.ts
index 6929c90d22..98fb3437ba 100644
--- a/packages/service-worker/src/low_level.ts
+++ b/packages/service-worker/src/low_level.ts
@@ -11,27 +11,26 @@ import {filter, map, publish, switchMap, take, tap} from 'rxjs/operators';
 
 export const ERR_SW_NOT_SUPPORTED = 'Service workers are disabled or not supported by this browser';
 
-export interface Version {
-  hash: string;
-  appData?: Object;
-}
-
 /**
+ * An event emitted when a new version of the app is available.
+ *
  * @experimental
  */
 export interface UpdateAvailableEvent {
   type: 'UPDATE_AVAILABLE';
-  current: Version;
-  available: Version;
+  current: {hash: string, appData?: Object};
+  available: {hash: string, appData?: Object};
 }
 
 /**
+ * An event emitted when a new version of the app has been downloaded and activated.
+ *
  * @experimental
  */
 export interface UpdateActivatedEvent {
   type: 'UPDATE_ACTIVATED';
-  previous?: Version;
-  current: Version;
+  previous?: {hash: string, appData?: Object};
+  current: {hash: string, appData?: Object};
 }
 
 export type IncomingEvent = UpdateAvailableEvent | UpdateActivatedEvent;
@@ -52,7 +51,7 @@ function errorObservable(message: string): Observable<any> {
 
 /**
  * @experimental
-*/
+ */
 export class NgswCommChannel {
   /**
    * @internal
diff --git a/tools/public_api_guard/service-worker/service-worker.d.ts b/tools/public_api_guard/service-worker/service-worker.d.ts
index e05787c01a..c5136b3209 100644
--- a/tools/public_api_guard/service-worker/service-worker.d.ts
+++ b/tools/public_api_guard/service-worker/service-worker.d.ts
@@ -27,3 +27,29 @@ export declare class SwUpdate {
     activateUpdate(): Promise<void>;
     checkForUpdate(): Promise<void>;
 }
+
+/** @experimental */
+export interface UpdateActivatedEvent {
+    current: {
+        hash: string;
+        appData?: Object;
+    };
+    previous?: {
+        hash: string;
+        appData?: Object;
+    };
+    type: 'UPDATE_ACTIVATED';
+}
+
+/** @experimental */
+export interface UpdateAvailableEvent {
+    available: {
+        hash: string;
+        appData?: Object;
+    };
+    current: {
+        hash: string;
+        appData?: Object;
+    };
+    type: 'UPDATE_AVAILABLE';
+}