diff --git a/src/ActiveRoomObserver.ts b/src/ActiveRoomObserver.ts
index 1126dc9496..0be49a24ea 100644
--- a/src/ActiveRoomObserver.ts
+++ b/src/ActiveRoomObserver.ts
@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import RoomViewStore from './stores/RoomViewStore';
+import { EventSubscription } from 'fbemitter';
 
 type Listener = (isActive: boolean) => void;
 
@@ -30,7 +31,7 @@ type Listener = (isActive: boolean) => void;
 export class ActiveRoomObserver {
     private listeners: {[key: string]: Listener[]} = {};
     private _activeRoomId = RoomViewStore.getRoomId();
-    private readonly roomStoreToken: string;
+    private readonly roomStoreToken: EventSubscription;
 
     constructor() {
         // TODO: We could self-destruct when the last listener goes away, or at least stop listening.
diff --git a/src/components/views/voip/CallPreview.tsx b/src/components/views/voip/CallPreview.tsx
index ddcb9057ec..895d9773e4 100644
--- a/src/components/views/voip/CallPreview.tsx
+++ b/src/components/views/voip/CallPreview.tsx
@@ -30,6 +30,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 import UIStore from '../../../stores/UIStore';
 import { lerp } from '../../../utils/AnimationUtils';
 import { MarkedExecution } from '../../../utils/MarkedExecution';
+import { EventSubscription } from 'fbemitter';
 
 const PIP_VIEW_WIDTH = 336;
 const PIP_VIEW_HEIGHT = 232;
@@ -108,7 +109,7 @@ function getPrimarySecondaryCalls(calls: MatrixCall[]): [MatrixCall, MatrixCall[
  */
 @replaceableComponent("views.voip.CallPreview")
 export default class CallPreview extends React.Component<IProps, IState> {
-    private roomStoreToken: any;
+    private roomStoreToken: EventSubscription;
     private dispatcherRef: string;
     private settingsWatcherRef: string;
     private callViewWrapper = createRef<HTMLDivElement>();
@@ -240,7 +241,7 @@ export default class CallPreview extends React.Component<IProps, IState> {
         this.scheduledUpdate.mark();
     };
 
-    private onRoomViewStoreUpdate = (payload) => {
+    private onRoomViewStoreUpdate = () => {
         if (RoomViewStore.getRoomId() === this.state.roomId) return;
 
         const roomId = RoomViewStore.getRoomId();