diff --git a/src/components/structures/RoomView.tsx b/src/components/structures/RoomView.tsx
index 8d85b54df72..221d2151efd 100644
--- a/src/components/structures/RoomView.tsx
+++ b/src/components/structures/RoomView.tsx
@@ -223,6 +223,7 @@ export interface IRoomState {
     narrow: boolean;
     // List of undecryptable events currently visible on-screen
     visibleDecryptionFailures?: MatrixEvent[];
+    msc3946ProcessDynamicPredecessor: boolean;
 }
 
 interface LocalRoomViewProps {
@@ -416,6 +417,7 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
             liveTimeline: undefined,
             narrow: false,
             visibleDecryptionFailures: [],
+            msc3946ProcessDynamicPredecessor: SettingsStore.getValue("feature_dynamic_room_predecessors"),
         };
 
         this.dispatcherRef = dis.register(this.onAction);
@@ -467,6 +469,9 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
             ),
             SettingsStore.watchSetting("urlPreviewsEnabled", null, this.onUrlPreviewsEnabledChange),
             SettingsStore.watchSetting("urlPreviewsEnabled_e2ee", null, this.onUrlPreviewsEnabledChange),
+            SettingsStore.watchSetting("feature_dynamic_room_predecessors", null, (...[, , , value]) =>
+                this.setState({ msc3946ProcessDynamicPredecessor: value as boolean }),
+            ),
         ];
     }
 
@@ -1798,10 +1803,8 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
     };
 
     private getOldRoom(): Room | null {
-        const createEvent = this.state.room.currentState.getStateEvents(EventType.RoomCreate, "");
-        if (!createEvent || !createEvent.getContent()["predecessor"]) return null;
-
-        return this.context.client.getRoom(createEvent.getContent()["predecessor"]["room_id"]);
+        const { roomId } = this.state.room?.findPredecessor(this.state.msc3946ProcessDynamicPredecessor) || {};
+        return this.context.client?.getRoom(roomId) || null;
     }
 
     public getHiddenHighlightCount(): number {
diff --git a/src/contexts/RoomContext.ts b/src/contexts/RoomContext.ts
index f5990205224..9d3eeff564f 100644
--- a/src/contexts/RoomContext.ts
+++ b/src/contexts/RoomContext.ts
@@ -65,6 +65,7 @@ const RoomContext = createContext<IRoomState>({
     liveTimeline: undefined,
     narrow: false,
     activeCall: null,
+    msc3946ProcessDynamicPredecessor: false,
 });
 RoomContext.displayName = "RoomContext";
 export default RoomContext;
diff --git a/test/components/structures/RoomView-test.tsx b/test/components/structures/RoomView-test.tsx
index b740ffe5a3e..e9860f5bbaa 100644
--- a/test/components/structures/RoomView-test.tsx
+++ b/test/components/structures/RoomView-test.tsx
@@ -55,6 +55,7 @@ const RoomView = wrapInMatrixClientContext(_RoomView);
 describe("RoomView", () => {
     let cli: MockedObject<MatrixClient>;
     let room: Room;
+    let rooms: Map<string, Room>;
     let roomCount = 0;
     let stores: SdkContextClass;
 
@@ -64,8 +65,11 @@ describe("RoomView", () => {
         cli = mocked(MatrixClientPeg.get());
 
         room = new Room(`!${roomCount++}:example.org`, cli, "@alice:example.org");
+        jest.spyOn(room, "findPredecessor");
         room.getPendingEvents = () => [];
-        cli.getRoom.mockImplementation(() => room);
+        rooms = new Map();
+        rooms.set(room.roomId, room);
+        cli.getRoom.mockImplementation((roomId: string | undefined) => rooms.get(roomId || "") || null);
         // Re-emit certain events on the mocked client
         room.on(RoomEvent.Timeline, (...args) => cli.emit(RoomEvent.Timeline, ...args));
         room.on(RoomEvent.TimelineReset, (...args) => cli.emit(RoomEvent.TimelineReset, ...args));
@@ -158,6 +162,42 @@ describe("RoomView", () => {
     const getRoomViewInstance = async (): Promise<_RoomView> =>
         (await mountRoomView()).find(_RoomView).instance() as _RoomView;
 
+    it("when there is no room predecessor, getHiddenHighlightCount should return 0", async () => {
+        const instance = await getRoomViewInstance();
+        expect(instance.getHiddenHighlightCount()).toBe(0);
+    });
+
+    describe("when there is an old room", () => {
+        let instance: _RoomView;
+        let oldRoom: Room;
+
+        beforeEach(async () => {
+            instance = await getRoomViewInstance();
+            oldRoom = new Room("!old:example.com", cli, cli.getSafeUserId());
+            rooms.set(oldRoom.roomId, oldRoom);
+            jest.spyOn(room, "findPredecessor").mockReturnValue({ roomId: oldRoom.roomId, eventId: null });
+        });
+
+        it("and it has 0 unreads, getHiddenHighlightCount should return 0", async () => {
+            jest.spyOn(oldRoom, "getUnreadNotificationCount").mockReturnValue(0);
+            expect(instance.getHiddenHighlightCount()).toBe(0);
+            // assert that msc3946ProcessDynamicPredecessor is false by default
+            expect(room.findPredecessor).toHaveBeenCalledWith(false);
+        });
+
+        it("and it has 23 unreads, getHiddenHighlightCount should return 23", async () => {
+            jest.spyOn(oldRoom, "getUnreadNotificationCount").mockReturnValue(23);
+            expect(instance.getHiddenHighlightCount()).toBe(23);
+        });
+
+        it("and feature_dynamic_room_predecessors is enabled it should pass the setting to findPredecessor", async () => {
+            SettingsStore.setValue("feature_dynamic_room_predecessors", null, SettingLevel.DEVICE, true);
+            expect(instance.getHiddenHighlightCount()).toBe(0);
+            expect(room.findPredecessor).toHaveBeenCalledWith(true);
+            SettingsStore.setValue("feature_dynamic_room_predecessors", null, SettingLevel.DEVICE, null);
+        });
+    });
+
     it("updates url preview visibility on encryption state change", async () => {
         // we should be starting unencrypted
         expect(cli.isCryptoEnabled()).toEqual(false);
@@ -248,6 +288,7 @@ describe("RoomView", () => {
 
         beforeEach(async () => {
             localRoom = room = await createDmLocalRoom(cli, [new DirectoryMember({ user_id: "@user:example.com" })]);
+            rooms.set(localRoom.roomId, localRoom);
             cli.store.storeRoom(room);
         });
 
diff --git a/test/components/views/rooms/SendMessageComposer-test.tsx b/test/components/views/rooms/SendMessageComposer-test.tsx
index 1005758ae99..7dcc89be1ef 100644
--- a/test/components/views/rooms/SendMessageComposer-test.tsx
+++ b/test/components/views/rooms/SendMessageComposer-test.tsx
@@ -78,6 +78,7 @@ describe("<SendMessageComposer/>", () => {
         resizing: false,
         narrow: false,
         activeCall: null,
+        msc3946ProcessDynamicPredecessor: false,
     };
     describe("createMessageContent", () => {
         const permalinkCreator = jest.fn() as any;
diff --git a/test/test-utils/room.ts b/test/test-utils/room.ts
index d20200bef18..af2487a6043 100644
--- a/test/test-utils/room.ts
+++ b/test/test-utils/room.ts
@@ -86,6 +86,7 @@ export function getRoomContext(room: Room, override: Partial<IRoomState>): IRoom
         resizing: false,
         narrow: false,
         activeCall: null,
+        msc3946ProcessDynamicPredecessor: false,
 
         ...override,
     };