diff --git a/src/ClientContext.tsx b/src/ClientContext.tsx
index 8ba26b4..8bd0412 100644
--- a/src/ClientContext.tsx
+++ b/src/ClientContext.tsx
@@ -258,7 +258,11 @@ export const ClientProvider: FC<Props> = ({ children }) => {
   }, [history]);
 
   useEffect(() => {
-    if (client) {
+    // To protect against multiple sessions writing to the same storage
+    // simultaneously, we send a to-device message that shuts down all other
+    // running instances of the app. This isn't necessary if the app is running
+    // in a widget though, since then it'll be mostly stateless.
+    if (!widget && client) {
       const loadTime = Date.now();
 
       const onToDeviceEvent = (event: MatrixEvent) => {
diff --git a/src/widget.ts b/src/widget.ts
index b6e7b98..c0cdde9 100644
--- a/src/widget.ts
+++ b/src/widget.ts
@@ -106,7 +106,6 @@ export const widget: WidgetHelpers | null = (() => {
         EventType.CallSDPStreamMetadataChanged,
         EventType.CallSDPStreamMetadataChangedPrefix,
         EventType.CallReplaces,
-        "org.matrix.call_duplicate_session",
       ];
 
       const client = createRoomWidgetClient(