diff --git a/spec/unit/matrixrtc/MatrixRTCSession.spec.ts b/spec/unit/matrixrtc/MatrixRTCSession.spec.ts
index 7fc4b2f7c..e7e64c9cb 100644
--- a/spec/unit/matrixrtc/MatrixRTCSession.spec.ts
+++ b/spec/unit/matrixrtc/MatrixRTCSession.spec.ts
@@ -26,6 +26,8 @@ const mockFocus = { type: "mock" };
 
 const textEncoder = new TextEncoder();
 
+const callSession = { id: "", application: "m.call" };
+
 describe("MatrixRTCSession", () => {
     let client: MatrixClient;
     let sess: MatrixRTCSession | undefined;
@@ -49,14 +51,14 @@ describe("MatrixRTCSession", () => {
         it("creates a room-scoped session from room state", () => {
             const mockRoom = makeMockRoom([membershipTemplate]);
 
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships.length).toEqual(1);
-            expect(sess?.memberships[0].callId).toEqual("");
+            expect(sess?.memberships[0].sessionDescription.id).toEqual("");
             expect(sess?.memberships[0].scope).toEqual("m.room");
             expect(sess?.memberships[0].application).toEqual("m.call");
             expect(sess?.memberships[0].deviceId).toEqual("AAAAAAA");
             expect(sess?.memberships[0].isExpired()).toEqual(false);
-            expect(sess?.callId).toEqual("");
+            expect(sess?.sessionDescription.id).toEqual("");
         });
 
         it("ignores memberships where application is not m.call", () => {
@@ -64,7 +66,7 @@ describe("MatrixRTCSession", () => {
                 application: "not-m.call",
             });
             const mockRoom = makeMockRoom([testMembership]);
-            const sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships).toHaveLength(0);
         });
 
@@ -74,7 +76,7 @@ describe("MatrixRTCSession", () => {
                 scope: "m.room",
             });
             const mockRoom = makeMockRoom([testMembership]);
-            const sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships).toHaveLength(0);
         });
 
@@ -86,7 +88,7 @@ describe("MatrixRTCSession", () => {
             const mockRoom = makeMockRoom([membershipTemplate, expiredMembership]);
 
             jest.advanceTimersByTime(2000);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships.length).toEqual(1);
             expect(sess?.memberships[0].deviceId).toEqual("AAAAAAA");
             jest.useRealTimers();
@@ -95,7 +97,7 @@ describe("MatrixRTCSession", () => {
         it("ignores memberships events of members not in the room", () => {
             const mockRoom = makeMockRoom([membershipTemplate]);
             mockRoom.hasMembershipState = (state) => state === KnownMembership.Join;
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships.length).toEqual(0);
         });
 
@@ -106,14 +108,14 @@ describe("MatrixRTCSession", () => {
             expiredMembership.created_ts = 500;
             expiredMembership.expires = 1000;
             const mockRoom = makeMockRoom([expiredMembership]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships[0].getAbsoluteExpiry()).toEqual(1500);
             jest.useRealTimers();
         });
 
         it("returns empty session if no membership events are present", () => {
             const mockRoom = makeMockRoom([]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess?.memberships).toHaveLength(0);
         });
 
@@ -148,7 +150,7 @@ describe("MatrixRTCSession", () => {
                     }),
                 }),
             };
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom as unknown as Room);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom as unknown as Room, callSession);
             expect(sess.memberships).toHaveLength(0);
         });
 
@@ -183,7 +185,7 @@ describe("MatrixRTCSession", () => {
                     }),
                 }),
             };
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom as unknown as Room);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom as unknown as Room, callSession);
             expect(sess.memberships).toHaveLength(0);
         });
 
@@ -191,7 +193,7 @@ describe("MatrixRTCSession", () => {
             const testMembership = Object.assign({}, membershipTemplate);
             (testMembership.device_id as string | undefined) = undefined;
             const mockRoom = makeMockRoom([testMembership]);
-            const sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            const sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess.memberships).toHaveLength(0);
         });
 
@@ -199,23 +201,7 @@ describe("MatrixRTCSession", () => {
             const testMembership = Object.assign({}, membershipTemplate);
             (testMembership.call_id as string | undefined) = undefined;
             const mockRoom = makeMockRoom([testMembership]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
-            expect(sess.memberships).toHaveLength(0);
-        });
-
-        it("ignores memberships with no scope", () => {
-            const testMembership = Object.assign({}, membershipTemplate);
-            (testMembership.scope as string | undefined) = undefined;
-            const mockRoom = makeMockRoom([testMembership]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
-            expect(sess.memberships).toHaveLength(0);
-        });
-
-        it("ignores anything that's not a room-scoped call (for now)", () => {
-            const testMembership = Object.assign({}, membershipTemplate);
-            testMembership.scope = "m.user";
-            const mockRoom = makeMockRoom([testMembership]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess.memberships).toHaveLength(0);
         });
     });
@@ -230,7 +216,7 @@ describe("MatrixRTCSession", () => {
                 Object.assign({}, membershipTemplate, { device_id: "bar", created_ts: 2000 }),
             ]);
 
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             expect(sess.getOldestMembership()!.deviceId).toEqual("old");
             jest.useRealTimers();
         });
@@ -255,7 +241,7 @@ describe("MatrixRTCSession", () => {
                 Object.assign({}, membershipTemplate, { device_id: "bar", created_ts: 2000 }),
             ]);
 
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
             sess.joinRoomSession([{ type: "livekit", livekit_service_url: "htts://test.org" }], {
                 type: "livekit",
@@ -275,7 +261,7 @@ describe("MatrixRTCSession", () => {
                 Object.assign({}, membershipTemplate, { device_id: "bar", created_ts: 2000 }),
             ]);
 
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
             sess.joinRoomSession([{ type: "livekit", livekit_service_url: "htts://test.org" }], {
                 type: "livekit",
@@ -302,7 +288,7 @@ describe("MatrixRTCSession", () => {
             client._unstable_updateDelayedEvent = jest.fn();
 
             mockRoom = makeMockRoom([]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
         });
 
         afterEach(async () => {
@@ -385,7 +371,7 @@ describe("MatrixRTCSession", () => {
     describe("onMembershipsChanged", () => {
         it("does not emit if no membership changes", () => {
             const mockRoom = makeMockRoom([membershipTemplate]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
             const onMembershipsChanged = jest.fn();
             sess.on(MatrixRTCSessionEvent.MembershipsChanged, onMembershipsChanged);
@@ -396,7 +382,7 @@ describe("MatrixRTCSession", () => {
 
         it("emits on membership changes", () => {
             const mockRoom = makeMockRoom([membershipTemplate]);
-            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
             const onMembershipsChanged = jest.fn();
             sess.on(MatrixRTCSessionEvent.MembershipsChanged, onMembershipsChanged);
@@ -451,7 +437,7 @@ describe("MatrixRTCSession", () => {
                 client.encryptAndSendToDevice = sendToDeviceMock;
 
                 mockRoom = makeMockRoom([]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
             });
 
             afterEach(async () => {
@@ -570,7 +556,7 @@ describe("MatrixRTCSession", () => {
                         device_id: "BBBBBBB",
                     });
                     const mockRoom = makeMockRoom([membershipTemplate, member2]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                     // joining will trigger an initial key send
                     const keysSentPromise1 = new Promise<EncryptionKeysEventContent>((resolve) => {
@@ -619,7 +605,7 @@ describe("MatrixRTCSession", () => {
                 jest.useFakeTimers();
                 try {
                     const mockRoom = makeMockRoom([membershipTemplate]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                     const keysSentPromise1 = new Promise<EncryptionKeysEventContent>((resolve) => {
                         sendEventMock.mockImplementation((_roomId, _evType, payload) => resolve(payload));
@@ -670,7 +656,7 @@ describe("MatrixRTCSession", () => {
                     const mockRoom = makeMockRoom([member1, member2]);
                     mockRoomState(mockRoom, [member1, member2]);
 
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                     sess.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
 
                     await keysSentPromise1;
@@ -715,7 +701,7 @@ describe("MatrixRTCSession", () => {
                     };
 
                     const mockRoom = makeMockRoom([member1, member2]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                     sess.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
 
                     await keysSentPromise1;
@@ -779,7 +765,7 @@ describe("MatrixRTCSession", () => {
                         device_id: "BBBBBBB",
                     });
                     const mockRoom = makeMockRoom([membershipTemplate, member2]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                     const onMyEncryptionKeyChanged = jest.fn();
                     sess.on(
@@ -869,7 +855,7 @@ describe("MatrixRTCSession", () => {
 
                         if (i === 0) {
                             // if first time around then set up the session
-                            sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                            sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                             sess.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                         } else {
                             // otherwise update the state reducing the membership each time in order to trigger key rotation
@@ -895,7 +881,7 @@ describe("MatrixRTCSession", () => {
                 jest.useFakeTimers();
                 try {
                     const mockRoom = makeMockRoom([membershipTemplate]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                     const keysSentPromise1 = new Promise((resolve) => {
                         sendEventMock.mockImplementation(resolve);
@@ -936,7 +922,7 @@ describe("MatrixRTCSession", () => {
                     });
 
                     const mockRoom = makeMockRoom([membershipTemplate]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                     sess!.joinRoomSession([mockFocus], mockFocus, {
                         manageMediaKeys: true,
@@ -959,7 +945,7 @@ describe("MatrixRTCSession", () => {
         describe("receiving", () => {
             it("collects keys from encryption events", async () => {
                 const mockRoom = makeMockRoom([membershipTemplate]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                 sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 mockRoom.emitTimelineEvent(
                     makeMockEvent("io.element.call.encryption_keys", "@bob:example.org", "1234roomId", {
@@ -984,7 +970,7 @@ describe("MatrixRTCSession", () => {
 
             it("collects keys at non-zero indices", async () => {
                 const mockRoom = makeMockRoom([membershipTemplate]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                 sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 mockRoom.emitTimelineEvent(
                     makeMockEvent("io.element.call.encryption_keys", "@bob:example.org", "1234roomId", {
@@ -1010,7 +996,7 @@ describe("MatrixRTCSession", () => {
 
             it("collects keys by merging", async () => {
                 const mockRoom = makeMockRoom([membershipTemplate]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                 sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 mockRoom.emitTimelineEvent(
                     makeMockEvent("io.element.call.encryption_keys", "@bob:example.org", "1234roomId", {
@@ -1061,7 +1047,7 @@ describe("MatrixRTCSession", () => {
 
             it("ignores older keys at same index", async () => {
                 const mockRoom = makeMockRoom([membershipTemplate]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                 sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 mockRoom.emitTimelineEvent(
                     makeMockEvent(
@@ -1120,7 +1106,7 @@ describe("MatrixRTCSession", () => {
 
             it("key timestamps are treated as monotonic", async () => {
                 const mockRoom = makeMockRoom([membershipTemplate]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
                 sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 mockRoom.emitTimelineEvent(
                     makeMockEvent(
@@ -1164,7 +1150,7 @@ describe("MatrixRTCSession", () => {
 
             it("ignores keys event for the local participant", () => {
                 const mockRoom = makeMockRoom([membershipTemplate]);
-                sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                 sess!.joinRoomSession([mockFocus], mockFocus, { manageMediaKeys: true });
                 mockRoom.emitTimelineEvent(
@@ -1187,7 +1173,7 @@ describe("MatrixRTCSession", () => {
                 jest.useFakeTimers();
                 try {
                     const mockRoom = makeMockRoom([membershipTemplate]);
-                    sess = MatrixRTCSession.roomSessionForRoom(client, mockRoom);
+                    sess = MatrixRTCSession.sessionForRoom(client, mockRoom, callSession);
 
                     // defaults to getTs()
                     jest.setSystemTime(1000);
diff --git a/spec/unit/matrixrtc/MatrixRTCSessionManager.spec.ts b/spec/unit/matrixrtc/MatrixRTCSessionManager.spec.ts
index 377e0eaf0..9472dc16e 100644
--- a/spec/unit/matrixrtc/MatrixRTCSessionManager.spec.ts
+++ b/spec/unit/matrixrtc/MatrixRTCSessionManager.spec.ts
@@ -16,8 +16,9 @@ limitations under the License.
 
 import { ClientEvent, EventTimeline, MatrixClient } from "../../../src";
 import { RoomStateEvent } from "../../../src/models/room-state";
-import { MatrixRTCSessionManagerEvents } from "../../../src/matrixrtc/MatrixRTCSessionManager";
+import { MatrixRTCSessionManager, MatrixRTCSessionManagerEvents } from "../../../src/matrixrtc/MatrixRTCSessionManager";
 import { makeMockRoom, membershipTemplate, mockRoomState } from "./mocks";
+import { logger } from "../../../src/logger";
 
 describe("MatrixRTCSessionManager", () => {
     let client: MatrixClient;
@@ -47,6 +48,21 @@ describe("MatrixRTCSessionManager", () => {
         }
     });
 
+    it("Doesn't fire event if unrelated sessions starts", () => {
+        const onStarted = jest.fn();
+        client.matrixRTC.on(MatrixRTCSessionManagerEvents.SessionStarted, onStarted);
+
+        try {
+            const room1 = makeMockRoom([{ ...membershipTemplate, application: "m.other" }]);
+            jest.spyOn(client, "getRooms").mockReturnValue([room1]);
+
+            client.emit(ClientEvent.Room, room1);
+            expect(onStarted).not.toHaveBeenCalled();
+        } finally {
+            client.matrixRTC.off(MatrixRTCSessionManagerEvents.SessionStarted, onStarted);
+        }
+    });
+
     it("Fires event when session ends", () => {
         const onEnded = jest.fn();
         client.matrixRTC.on(MatrixRTCSessionManagerEvents.SessionEnded, onEnded);
@@ -59,9 +75,75 @@ describe("MatrixRTCSessionManager", () => {
         mockRoomState(room1, [{ user_id: membershipTemplate.user_id }]);
 
         const roomState = room1.getLiveTimeline().getState(EventTimeline.FORWARDS)!;
-        const membEvent = roomState.getStateEvents("")[0];
+        const membEvent = roomState.getStateEvents("org.matrix.msc3401.call.member")[0];
         client.emit(RoomStateEvent.Events, membEvent, roomState, null);
 
         expect(onEnded).toHaveBeenCalledWith(room1.roomId, client.matrixRTC.getActiveRoomSession(room1));
     });
+
+    it("Fires correctly with for with custom sessionDescription", () => {
+        const onStarted = jest.fn();
+        const onEnded = jest.fn();
+        // create a session manager with a custom session description
+        const sessionManager = new MatrixRTCSessionManager(logger, client, { id: "test", application: "m.notCall" });
+
+        // manually start the session manager (its not the default one started by the client)
+        sessionManager.start();
+        sessionManager.on(MatrixRTCSessionManagerEvents.SessionEnded, onEnded);
+        sessionManager.on(MatrixRTCSessionManagerEvents.SessionStarted, onStarted);
+
+        try {
+            const room1 = makeMockRoom([{ ...membershipTemplate, application: "m.other" }]);
+            jest.spyOn(client, "getRooms").mockReturnValue([room1]);
+
+            client.emit(ClientEvent.Room, room1);
+            expect(onStarted).not.toHaveBeenCalled();
+            onStarted.mockClear();
+
+            const room2 = makeMockRoom([{ ...membershipTemplate, application: "m.notCall", call_id: "test" }]);
+            jest.spyOn(client, "getRooms").mockReturnValue([room1, room2]);
+
+            client.emit(ClientEvent.Room, room2);
+            expect(onStarted).toHaveBeenCalled();
+            onStarted.mockClear();
+
+            mockRoomState(room2, [{ user_id: membershipTemplate.user_id }]);
+            jest.spyOn(client, "getRoom").mockReturnValue(room2);
+
+            const roomState = room2.getLiveTimeline().getState(EventTimeline.FORWARDS)!;
+            const membEvent = roomState.getStateEvents("org.matrix.msc3401.call.member")[0];
+            client.emit(RoomStateEvent.Events, membEvent, roomState, null);
+            expect(onEnded).toHaveBeenCalled();
+            onEnded.mockClear();
+
+            mockRoomState(room1, [{ user_id: membershipTemplate.user_id }]);
+            jest.spyOn(client, "getRoom").mockReturnValue(room1);
+
+            const roomStateOther = room1.getLiveTimeline().getState(EventTimeline.FORWARDS)!;
+            const membEventOther = roomStateOther.getStateEvents("org.matrix.msc3401.call.member")[0];
+            client.emit(RoomStateEvent.Events, membEventOther, roomStateOther, null);
+            expect(onEnded).not.toHaveBeenCalled();
+        } finally {
+            client.matrixRTC.off(MatrixRTCSessionManagerEvents.SessionStarted, onStarted);
+            client.matrixRTC.off(MatrixRTCSessionManagerEvents.SessionEnded, onEnded);
+        }
+    });
+
+    it("Doesn't fire event if unrelated sessions ends", () => {
+        const onEnded = jest.fn();
+        client.matrixRTC.on(MatrixRTCSessionManagerEvents.SessionEnded, onEnded);
+        const room1 = makeMockRoom([{ ...membershipTemplate, application: "m.other_app" }]);
+        jest.spyOn(client, "getRooms").mockReturnValue([room1]);
+        jest.spyOn(client, "getRoom").mockReturnValue(room1);
+
+        client.emit(ClientEvent.Room, room1);
+
+        mockRoomState(room1, [{ user_id: membershipTemplate.user_id }]);
+
+        const roomState = room1.getLiveTimeline().getState(EventTimeline.FORWARDS)!;
+        const membEvent = roomState.getStateEvents("org.matrix.msc3401.call.member")[0];
+        client.emit(RoomStateEvent.Events, membEvent, roomState, null);
+
+        expect(onEnded).not.toHaveBeenCalledWith(room1.roomId, client.matrixRTC.getActiveRoomSession(room1));
+    });
 });
diff --git a/spec/unit/matrixrtc/MembershipManager.spec.ts b/spec/unit/matrixrtc/MembershipManager.spec.ts
index b5a4e22f1..e014730ba 100644
--- a/spec/unit/matrixrtc/MembershipManager.spec.ts
+++ b/spec/unit/matrixrtc/MembershipManager.spec.ts
@@ -64,6 +64,8 @@ function createAsyncHandle<T>(method: MockedFunction<any>) {
     return { reject, resolve };
 }
 
+const callSession = { id: "", application: "m.call" };
+
 describe("MembershipManager", () => {
     let client: MockClient;
     let room: Room;
@@ -95,12 +97,12 @@ describe("MembershipManager", () => {
 
     describe("isActivated()", () => {
         it("defaults to false", () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             expect(manager.isActivated()).toEqual(false);
         });
 
         it("returns true after join()", () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([]);
             expect(manager.isActivated()).toEqual(true);
         });
@@ -114,7 +116,7 @@ describe("MembershipManager", () => {
                 const updateDelayedEventHandle = createAsyncHandle<void>(client._unstable_updateDelayedEvent as Mock);
 
                 // Test
-                const memberManager = new MembershipManager(undefined, room, client, () => undefined);
+                const memberManager = new MembershipManager(undefined, room, client, () => undefined, callSession);
                 memberManager.join([focus], focusActive);
                 // expects
                 await waitForMockCall(client.sendStateEvent, Promise.resolve({ event_id: "id" }));
@@ -130,7 +132,7 @@ describe("MembershipManager", () => {
                         focus_active: focusActive,
                         scope: "m.room",
                     },
-                    "_@alice:example.org_AAAAAAA",
+                    "_@alice:example.org_AAAAAAA_m.call",
                 );
                 updateDelayedEventHandle.resolve?.();
                 expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledWith(
@@ -138,13 +140,13 @@ describe("MembershipManager", () => {
                     { delay: 8000 },
                     "org.matrix.msc3401.call.member",
                     {},
-                    "_@alice:example.org_AAAAAAA",
+                    "_@alice:example.org_AAAAAAA_m.call",
                 );
                 expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledTimes(1);
             });
 
             it("reschedules delayed leave event if sending state cancels it", async () => {
-                const memberManager = new MembershipManager(undefined, room, client, () => undefined);
+                const memberManager = new MembershipManager(undefined, room, client, () => undefined, callSession);
                 const waitForSendState = waitForMockCall(client.sendStateEvent);
                 const waitForUpdateDelaye = waitForMockCallOnce(
                     client._unstable_updateDelayedEvent,
@@ -189,7 +191,7 @@ describe("MembershipManager", () => {
                         });
                     });
 
-                    const userStateKey = `${!useOwnedStateEvents ? "_" : ""}@alice:example.org_AAAAAAA`;
+                    const userStateKey = `${!useOwnedStateEvents ? "_" : ""}@alice:example.org_AAAAAAA_m.call`;
                     // preparing the delayed disconnect should handle ratelimiting
                     const sendDelayedStateAttempt = new Promise<void>((resolve) => {
                         const error = new MatrixError({ errcode: "M_LIMIT_EXCEEDED" });
@@ -220,6 +222,7 @@ describe("MembershipManager", () => {
                         room,
                         client,
                         () => undefined,
+                        callSession,
                     );
                     manager.join([focus], focusActive);
 
@@ -276,7 +279,7 @@ describe("MembershipManager", () => {
         describe("delayed leave event", () => {
             it("does not try again to schedule a delayed leave event if not supported", () => {
                 const delayedHandle = createAsyncHandle(client._unstable_sendDelayedStateEvent as Mock);
-                const manager = new MembershipManager({}, room, client, () => undefined);
+                const manager = new MembershipManager({}, room, client, () => undefined, callSession);
                 manager.join([focus], focusActive);
                 delayedHandle.reject?.(
                     new UnsupportedDelayedEventsEndpointError(
@@ -288,7 +291,7 @@ describe("MembershipManager", () => {
             });
             it("does try to schedule a delayed leave event again if rate limited", async () => {
                 const delayedHandle = createAsyncHandle(client._unstable_sendDelayedStateEvent as Mock);
-                const manager = new MembershipManager({}, room, client, () => undefined);
+                const manager = new MembershipManager({}, room, client, () => undefined, callSession);
                 manager.join([focus], focusActive);
                 delayedHandle.reject?.(new HTTPError("rate limited", 429, undefined));
                 await jest.advanceTimersByTimeAsync(5000);
@@ -300,6 +303,7 @@ describe("MembershipManager", () => {
                     room,
                     client,
                     () => undefined,
+                    callSession,
                 );
                 manager.join([focus], focusActive);
                 expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledWith(
@@ -307,7 +311,7 @@ describe("MembershipManager", () => {
                     { delay: 123456 },
                     "org.matrix.msc3401.call.member",
                     {},
-                    "_@alice:example.org_AAAAAAA",
+                    "_@alice:example.org_AAAAAAA_m.call",
                 );
             });
         });
@@ -319,6 +323,7 @@ describe("MembershipManager", () => {
                 room,
                 client,
                 () => undefined,
+                callSession,
             );
             // Join with the membership manager
             manager.join([focus], focusActive);
@@ -351,7 +356,13 @@ describe("MembershipManager", () => {
         });
 
         it("uses membershipEventExpiryMs from config", async () => {
-            const manager = new MembershipManager({ membershipEventExpiryMs: 1234567 }, room, client, () => undefined);
+            const manager = new MembershipManager(
+                { membershipEventExpiryMs: 1234567 },
+                room,
+                client,
+                () => undefined,
+                callSession,
+            );
 
             manager.join([focus], focusActive);
             await waitForMockCall(client.sendStateEvent);
@@ -370,12 +381,12 @@ describe("MembershipManager", () => {
                         type: "livekit",
                     },
                 },
-                "_@alice:example.org_AAAAAAA",
+                "_@alice:example.org_AAAAAAA_m.call",
             );
         });
 
         it("does nothing if join called when already joined", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive);
             await waitForMockCall(client.sendStateEvent);
             expect(client.sendStateEvent).toHaveBeenCalledTimes(1);
@@ -387,7 +398,7 @@ describe("MembershipManager", () => {
     describe("leave()", () => {
         // TODO add rate limit cases.
         it("resolves delayed leave event when leave is called", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive);
             await jest.advanceTimersByTimeAsync(1);
             await manager.leave();
@@ -395,7 +406,7 @@ describe("MembershipManager", () => {
             expect(client.sendStateEvent).toHaveBeenCalled();
         });
         it("send leave event when leave is called and resolving delayed leave fails", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive);
             await jest.advanceTimersByTimeAsync(1);
             (client._unstable_updateDelayedEvent as Mock<any>).mockRejectedValue("unknown");
@@ -406,11 +417,11 @@ describe("MembershipManager", () => {
                 room.roomId,
                 "org.matrix.msc3401.call.member",
                 {},
-                "_@alice:example.org_AAAAAAA",
+                "_@alice:example.org_AAAAAAA_m.call",
             );
         });
         it("does nothing if not joined", () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             expect(async () => await manager.leave()).not.toThrow();
             expect(client._unstable_sendDelayedStateEvent).not.toHaveBeenCalled();
             expect(client.sendStateEvent).not.toHaveBeenCalled();
@@ -420,7 +431,7 @@ describe("MembershipManager", () => {
     describe("getsActiveFocus", () => {
         it("gets the correct active focus with oldest_membership", () => {
             const getOldestMembership = jest.fn();
-            const manager = new MembershipManager({}, room, client, getOldestMembership);
+            const manager = new MembershipManager({}, room, client, getOldestMembership, callSession);
             // Before joining the active focus should be undefined (see FocusInUse on MatrixRTCSession)
             expect(manager.getActiveFocus()).toBe(undefined);
             manager.join([focus], focusActive);
@@ -455,7 +466,7 @@ describe("MembershipManager", () => {
         });
 
         it("does not provide focus if the selection method is unknown", () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], Object.assign(focusActive, { type: "unknown_type" }));
             expect(manager.getActiveFocus()).toBe(undefined);
         });
@@ -463,7 +474,7 @@ describe("MembershipManager", () => {
 
     describe("onRTCSessionMemberUpdate()", () => {
         it("does nothing if not joined", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             await manager.onRTCSessionMemberUpdate([mockCallMembership(membershipTemplate, room.roomId)]);
             await jest.advanceTimersToNextTimerAsync();
             expect(client.sendStateEvent).not.toHaveBeenCalled();
@@ -471,7 +482,7 @@ describe("MembershipManager", () => {
             expect(client._unstable_updateDelayedEvent).not.toHaveBeenCalled();
         });
         it("does nothing if own membership still present", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive);
             await jest.advanceTimersByTimeAsync(1);
             const myMembership = (client.sendStateEvent as Mock).mock.calls[0][2];
@@ -495,7 +506,7 @@ describe("MembershipManager", () => {
             expect(client._unstable_updateDelayedEvent).not.toHaveBeenCalled();
         });
         it("recreates membership if it is missing", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive);
             await jest.advanceTimersByTimeAsync(1);
             // clearing all mocks before checking what happens when calling: `onRTCSessionMemberUpdate`
@@ -513,7 +524,7 @@ describe("MembershipManager", () => {
         });
 
         it("updates the UpdateExpiry entry in the action scheduler", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive);
             await jest.advanceTimersByTimeAsync(1);
             // clearing all mocks before checking what happens when calling: `onRTCSessionMemberUpdate`
@@ -547,6 +558,7 @@ describe("MembershipManager", () => {
                 room,
                 client,
                 () => undefined,
+                { id: "", application: "m.call" },
             );
             manager.join([focus], focusActive);
             await jest.advanceTimersByTimeAsync(1);
@@ -578,6 +590,7 @@ describe("MembershipManager", () => {
                 room,
                 client,
                 () => undefined,
+                { id: "", application: "m.call" },
             );
             manager.join([focus], focusActive);
             await waitForMockCall(client.sendStateEvent);
@@ -600,14 +613,14 @@ describe("MembershipManager", () => {
     });
     describe("status updates", () => {
         it("starts 'Disconnected'", () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             expect(manager.status).toBe(Status.Disconnected);
         });
         it("emits 'Connection' and 'Connected' after join", async () => {
             const handleDelayedEvent = createAsyncHandle<void>(client._unstable_sendDelayedStateEvent);
             const handleStateEvent = createAsyncHandle<void>(client.sendStateEvent);
 
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             expect(manager.status).toBe(Status.Disconnected);
             const connectEmit = jest.fn();
             manager.on(MembershipManagerEvent.StatusChanged, connectEmit);
@@ -621,7 +634,7 @@ describe("MembershipManager", () => {
             expect(connectEmit).toHaveBeenCalledWith(Status.Connecting, Status.Connected);
         });
         it("emits 'Disconnecting' and 'Disconnected' after leave", async () => {
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             const connectEmit = jest.fn();
             manager.on(MembershipManagerEvent.StatusChanged, connectEmit);
             manager.join([focus], focusActive);
@@ -637,7 +650,7 @@ describe("MembershipManager", () => {
             it("sends retry if call membership event is still valid at time of retry", async () => {
                 const handle = createAsyncHandle(client._unstable_sendDelayedStateEvent);
 
-                const manager = new MembershipManager({}, room, client, () => undefined);
+                const manager = new MembershipManager({}, room, client, () => undefined, callSession);
                 manager.join([focus], focusActive);
                 expect(client._unstable_sendDelayedStateEvent).toHaveBeenCalledTimes(1);
 
@@ -664,7 +677,7 @@ describe("MembershipManager", () => {
                         new Headers({ "Retry-After": "1" }),
                     ),
                 );
-                const manager = new MembershipManager({}, room, client, () => undefined);
+                const manager = new MembershipManager({}, room, client, () => undefined, callSession);
                 // Should call _unstable_sendDelayedStateEvent but not sendStateEvent because of the
                 // RateLimit error.
                 manager.join([focus], focusActive);
@@ -684,7 +697,7 @@ describe("MembershipManager", () => {
             it("abandons retry loop if leave() was called before sending state event", async () => {
                 const handle = createAsyncHandle(client._unstable_sendDelayedStateEvent);
 
-                const manager = new MembershipManager({}, room, client, () => undefined);
+                const manager = new MembershipManager({}, room, client, () => undefined, callSession);
                 manager.join([focus], focusActive);
                 handle.reject?.(
                     new MatrixError(
@@ -719,7 +732,7 @@ describe("MembershipManager", () => {
                         new Headers({ "Retry-After": "1" }),
                     ),
                 );
-                const manager = new MembershipManager({}, room, client, () => undefined);
+                const manager = new MembershipManager({}, room, client, () => undefined, callSession);
                 manager.join([focus], focusActive);
 
                 // Hit rate limit
@@ -752,7 +765,7 @@ describe("MembershipManager", () => {
                     new Headers({ "Retry-After": "2" }),
                 ),
             );
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive, delayEventSendError);
 
             for (let i = 0; i < 10; i++) {
@@ -772,7 +785,7 @@ describe("MembershipManager", () => {
                     new Headers({ "Retry-After": "1" }),
                 ),
             );
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive, delayEventRestartError);
 
             for (let i = 0; i < 10; i++) {
@@ -783,7 +796,7 @@ describe("MembershipManager", () => {
         it("falls back to using pure state events when some error occurs while sending delayed events", async () => {
             const unrecoverableError = jest.fn();
             (client._unstable_sendDelayedStateEvent as Mock<any>).mockRejectedValue(new HTTPError("unknown", 601));
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive, unrecoverableError);
             await waitForMockCall(client.sendStateEvent);
             expect(unrecoverableError).not.toHaveBeenCalledWith();
@@ -797,6 +810,7 @@ describe("MembershipManager", () => {
                 room,
                 client,
                 () => undefined,
+                callSession,
             );
             manager.join([focus], focusActive, unrecoverableError);
             for (let retries = 0; retries < 7; retries++) {
@@ -814,7 +828,7 @@ describe("MembershipManager", () => {
             (client._unstable_sendDelayedStateEvent as Mock<any>).mockRejectedValue(
                 new UnsupportedDelayedEventsEndpointError("not supported", "sendDelayedStateEvent"),
             );
-            const manager = new MembershipManager({}, room, client, () => undefined);
+            const manager = new MembershipManager({}, room, client, () => undefined, callSession);
             manager.join([focus], focusActive, unrecoverableError);
             await jest.advanceTimersByTimeAsync(1);
 
@@ -828,7 +842,7 @@ it("Should prefix log with MembershipManager used", () => {
     const client = makeMockClient("@alice:example.org", "AAAAAAA");
     const room = makeMockRoom([membershipTemplate]);
 
-    const membershipManager = new MembershipManager(undefined, room, client, () => undefined, logger);
+    const membershipManager = new MembershipManager(undefined, room, client, () => undefined, callSession, logger);
 
     const spy = jest.spyOn(console, "error");
     // Double join
diff --git a/src/matrixrtc/CallMembership.ts b/src/matrixrtc/CallMembership.ts
index 5c62705d8..b3f50f028 100644
--- a/src/matrixrtc/CallMembership.ts
+++ b/src/matrixrtc/CallMembership.ts
@@ -18,6 +18,7 @@ import { type MatrixEvent } from "../matrix.ts";
 import { deepCompare } from "../utils.ts";
 import { type Focus } from "./focus.ts";
 import { isLivekitFocusActive } from "./LivekitFocus.ts";
+import { type SessionDescription } from "./MatrixRTCSession.ts";
 
 /**
  * The default duration in milliseconds that a membership is considered valid for.
@@ -130,6 +131,9 @@ export class CallMembership {
         return this.parentEvent.getId();
     }
 
+    /**
+     *  @deprecated Use sessionDescription.id instead.
+     */
     public get callId(): string {
         return this.membershipData.call_id;
     }
@@ -138,6 +142,13 @@ export class CallMembership {
         return this.membershipData.device_id;
     }
 
+    public get sessionDescription(): SessionDescription {
+        return {
+            application: this.membershipData.application,
+            id: this.membershipData.call_id,
+        };
+    }
+
     public get application(): string | undefined {
         return this.membershipData.application;
     }
diff --git a/src/matrixrtc/MatrixRTCSession.ts b/src/matrixrtc/MatrixRTCSession.ts
index 61340307f..883635571 100644
--- a/src/matrixrtc/MatrixRTCSession.ts
+++ b/src/matrixrtc/MatrixRTCSession.ts
@@ -26,7 +26,7 @@ import { type Focus } from "./focus.ts";
 import { KnownMembership } from "../@types/membership.ts";
 import { MembershipManager } from "./MembershipManager.ts";
 import { EncryptionManager, type IEncryptionManager } from "./EncryptionManager.ts";
-import { logDurationSync } from "../utils.ts";
+import { deepCompare, logDurationSync } from "../utils.ts";
 import { type Statistics, type RTCNotificationType } from "./types.ts";
 import { RoomKeyTransport } from "./RoomKeyTransport.ts";
 import type { IMembershipManager } from "./IMembershipManager.ts";
@@ -74,6 +74,14 @@ export interface SessionConfig {
     notificationType?: RTCNotificationType;
 }
 
+/**
+ * The session description is used to identify a session. Used in the state event.
+ */
+export interface SessionDescription {
+    id: string;
+    application: string;
+}
+
 // The names follow these principles:
 // - we use the technical term delay if the option is related to delayed events.
 // - we use delayedLeaveEvent if the option is related to the delayed leave event.
@@ -86,7 +94,7 @@ export interface MembershipConfig {
      * Use the new Manager.
      *
      * Default: `false`.
-     * @deprecated does nothing anymore we always default to the new memberhip manager.
+     * @deprecated does nothing anymore we always default to the new membership manager.
      */
     useNewMembershipManager?: boolean;
 
@@ -254,10 +262,27 @@ export class MatrixRTCSession extends TypedEventEmitter<
     }
 
     /**
-     * Returns all the call memberships for a room, oldest first
+     * Returns all the call memberships for a room that match the provided `sessionDescription`,
+     * oldest first.
+     *
+     * @deprecated Use `MatrixRTCSession.sessionMembershipsForRoom` instead.
      */
     public static callMembershipsForRoom(
         room: Pick<Room, "getLiveTimeline" | "roomId" | "hasMembershipState">,
+    ): CallMembership[] {
+        return MatrixRTCSession.sessionMembershipsForRoom(room, {
+            id: "",
+            application: "m.call",
+        });
+    }
+
+    /**
+     * Returns all the call memberships for a room that match the provided `sessionDescription`,
+     * oldest first.
+     */
+    public static sessionMembershipsForRoom(
+        room: Pick<Room, "getLiveTimeline" | "roomId" | "hasMembershipState">,
+        sessionDescription: SessionDescription,
     ): CallMembership[] {
         const logger = rootLogger.getChild(`[MatrixRTCSession ${room.roomId}]`);
         const roomState = room.getLiveTimeline().getState(EventTimeline.FORWARDS);
@@ -290,15 +315,10 @@ export class MatrixRTCSession extends TypedEventEmitter<
                 try {
                     const membership = new CallMembership(memberEvent, membershipData);
 
-                    if (membership.application !== "m.call") {
-                        // Only process MatrixRTC sessions associated with calls
-                        logger.info("Skipping non-call MatrixRTC session");
-                        continue;
-                    }
-
-                    if (membership.callId !== "" || membership.scope !== "m.room") {
-                        // for now, just ignore anything that isn't a room scope call
-                        logger.info(`Ignoring user-scoped call`);
+                    if (!deepCompare(membership.sessionDescription, sessionDescription)) {
+                        logger.info(
+                            `Ignoring membership of user ${membership.sender} for a different session:  ${JSON.stringify(membership.sessionDescription)}`,
+                        );
                         continue;
                     }
 
@@ -329,12 +349,33 @@ export class MatrixRTCSession extends TypedEventEmitter<
     }
 
     /**
-     * Return the MatrixRTC session for the room, whether there are currently active members or not
+     * Return the MatrixRTC session for the room.
+     * This returned session can be used to find out if there are active room call sessions
+     * for the requested room.
+     *
+     * This method is an alias for `MatrixRTCSession.sessionForRoom` with
+     * sessionDescription `{ id: "", application: "m.call" }`.
+     *
+     * @deprecated Use `MatrixRTCSession.sessionForRoom` with sessionDescription `{ id: "", application: "m.call" }` instead.
      */
     public static roomSessionForRoom(client: MatrixClient, room: Room): MatrixRTCSession {
-        const callMemberships = MatrixRTCSession.callMembershipsForRoom(room);
+        const callMemberships = MatrixRTCSession.sessionMembershipsForRoom(room, { id: "", application: "m.call" });
+        return new MatrixRTCSession(client, room, callMemberships, { id: "", application: "m.call" });
+    }
 
-        return new MatrixRTCSession(client, room, callMemberships);
+    /**
+     * Return the MatrixRTC session for the room.
+     * This returned session can be used to find out if there are active sessions
+     * for the requested room and `sessionDescription`.
+     */
+    public static sessionForRoom(
+        client: MatrixClient,
+        room: Room,
+        sessionDescription: SessionDescription,
+    ): MatrixRTCSession {
+        const callMemberships = MatrixRTCSession.sessionMembershipsForRoom(room, sessionDescription);
+
+        return new MatrixRTCSession(client, room, callMemberships, sessionDescription);
     }
 
     /**
@@ -379,10 +420,15 @@ export class MatrixRTCSession extends TypedEventEmitter<
             "getLiveTimeline" | "roomId" | "getVersion" | "hasMembershipState" | "on" | "off"
         >,
         public memberships: CallMembership[],
+        /**
+         * The session description is used to define the exact session this object is tracking.
+         * A session is distinct from another session if one of those properties differ: `roomSubset.roomId`, `sessionDescription.application`, `sessionDescription.id`.
+         */
+        public readonly sessionDescription: SessionDescription,
     ) {
         super();
         this.logger = rootLogger.getChild(`[MatrixRTCSession ${roomSubset.roomId}]`);
-        this._callId = memberships[0]?.callId;
+        this._callId = memberships[0]?.sessionDescription.id;
         const roomState = this.roomSubset.getLiveTimeline().getState(EventTimeline.FORWARDS);
         // TODO: double check if this is actually needed. Should be covered by refreshRoom in MatrixRTCSessionManager
         roomState?.on(RoomStateEvent.Members, this.onRoomMemberUpdate);
@@ -440,6 +486,7 @@ export class MatrixRTCSession extends TypedEventEmitter<
                 this.roomSubset,
                 this.client,
                 () => this.getOldestMembership(),
+                this.sessionDescription,
                 this.logger,
             );
 
@@ -648,9 +695,9 @@ export class MatrixRTCSession extends TypedEventEmitter<
      */
     private recalculateSessionMembers = (): void => {
         const oldMemberships = this.memberships;
-        this.memberships = MatrixRTCSession.callMembershipsForRoom(this.room);
+        this.memberships = MatrixRTCSession.sessionMembershipsForRoom(this.room, this.sessionDescription);
 
-        this._callId = this._callId ?? this.memberships[0]?.callId;
+        this._callId = this._callId ?? this.memberships[0]?.sessionDescription.id;
 
         const changed =
             oldMemberships.length != this.memberships.length ||
diff --git a/src/matrixrtc/MatrixRTCSessionManager.ts b/src/matrixrtc/MatrixRTCSessionManager.ts
index 2bf0d7409..cc25105d9 100644
--- a/src/matrixrtc/MatrixRTCSessionManager.ts
+++ b/src/matrixrtc/MatrixRTCSessionManager.ts
@@ -20,7 +20,7 @@ import { TypedEventEmitter } from "../models/typed-event-emitter.ts";
 import { type Room } from "../models/room.ts";
 import { type RoomState, RoomStateEvent } from "../models/room-state.ts";
 import { type MatrixEvent } from "../models/event.ts";
-import { MatrixRTCSession } from "./MatrixRTCSession.ts";
+import { MatrixRTCSession, type SessionDescription } from "./MatrixRTCSession.ts";
 import { EventType } from "../@types/event.ts";
 
 export enum MatrixRTCSessionManagerEvents {
@@ -37,6 +37,9 @@ type EventHandlerMap = {
 
 /**
  * Holds all active MatrixRTC session objects and creates new ones as events arrive.
+ * One `MatrixRTCSessionManager` is required for each MatrixRTC sessionDescription (application, session id) that the client wants to support.
+ * If no application type is specified in the constructor, the default is "m.call".
+ *
  * This interface is UNSTABLE and may change without warning.
  */
 export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionManagerEvents, EventHandlerMap> {
@@ -53,6 +56,7 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
     public constructor(
         rootLogger: Logger,
         private client: MatrixClient,
+        private readonly sessionDescription: SessionDescription = { id: "", application: "m.call" }, // Default to the Matrix Call application
     ) {
         super();
         this.logger = rootLogger.getChild("[MatrixRTCSessionManager]");
@@ -62,7 +66,7 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
         // We shouldn't need to null-check here, but matrix-client.spec.ts mocks getRooms
         // returning nothing, and breaks tests if you change it to return an empty array :'(
         for (const room of this.client.getRooms() ?? []) {
-            const session = MatrixRTCSession.roomSessionForRoom(this.client, room);
+            const session = MatrixRTCSession.sessionForRoom(this.client, room, this.sessionDescription);
             if (session.memberships.length > 0) {
                 this.roomSessions.set(room.roomId, session);
             }
@@ -96,7 +100,10 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
      */
     public getRoomSession(room: Room): MatrixRTCSession {
         if (!this.roomSessions.has(room.roomId)) {
-            this.roomSessions.set(room.roomId, MatrixRTCSession.roomSessionForRoom(this.client, room));
+            this.roomSessions.set(
+                room.roomId,
+                MatrixRTCSession.sessionForRoom(this.client, room, this.sessionDescription),
+            );
         }
 
         return this.roomSessions.get(room.roomId)!;
diff --git a/src/matrixrtc/MembershipManager.ts b/src/matrixrtc/MembershipManager.ts
index 73f2cdf2d..78fde0bc9 100644
--- a/src/matrixrtc/MembershipManager.ts
+++ b/src/matrixrtc/MembershipManager.ts
@@ -26,7 +26,7 @@ import { type CallMembership, DEFAULT_EXPIRE_DURATION, type SessionMembershipDat
 import { type Focus } from "./focus.ts";
 import { isMyMembership, Status } from "./types.ts";
 import { isLivekitFocusActive } from "./LivekitFocus.ts";
-import { type MembershipConfig } from "./MatrixRTCSession.ts";
+import { type SessionDescription, type MembershipConfig } from "./MatrixRTCSession.ts";
 import { ActionScheduler, type ActionUpdate } from "./MembershipManagerActionScheduler.ts";
 import { TypedEventEmitter } from "../models/typed-event-emitter.ts";
 import {
@@ -101,7 +101,7 @@ export enum MembershipActionType {
     //  -> MembershipActionType.Update if the timeout has passed so the next update is required.
 
     SendScheduledDelayedLeaveEvent = "SendScheduledDelayedLeaveEvent",
-    //  -> MembershipActionType.SendLeaveEvent on failiour (not found) we need to send the leave manually and cannot use the scheduled delayed event
+    //  -> MembershipActionType.SendLeaveEvent on failure (not found) we need to send the leave manually and cannot use the scheduled delayed event
     //  -> DelayedLeaveActionType.SendScheduledDelayedLeaveEvent on error we try again.
 
     SendLeaveEvent = "SendLeaveEvent",
@@ -294,6 +294,7 @@ export class MembershipManager
             | "_unstable_updateDelayedEvent"
         >,
         private getOldestMembership: () => CallMembership | undefined,
+        public readonly sessionDescription: SessionDescription,
         parentLogger?: Logger,
     ) {
         super();
@@ -700,7 +701,7 @@ export class MembershipManager
 
     // HELPERS
     private makeMembershipStateKey(localUserId: string, localDeviceId: string): string {
-        const stateKey = `${localUserId}_${localDeviceId}`;
+        const stateKey = `${localUserId}_${localDeviceId}_${this.sessionDescription.application}${this.sessionDescription.id}`;
         if (/^org\.matrix\.msc(3757|3779)\b/.exec(this.room.getVersion())) {
             return stateKey;
         } else {
@@ -713,9 +714,10 @@ export class MembershipManager
      */
     private makeMyMembership(expires: number): SessionMembershipData {
         return {
-            call_id: "",
+            // TODO: use the new format for m.rtc.member events where call_id becomes session.id
+            application: this.sessionDescription.application,
+            call_id: this.sessionDescription.id,
             scope: "m.room",
-            application: "m.call",
             device_id: this.deviceId,
             expires,
             focus_active: { type: "livekit", focus_selection: "oldest_membership" },