Merge pull request #4208 from element-hq/remove-legacy-mode

Remove MatrixRTC legacy mode
2026-08-29 05:29:53 +00:00 · 2026-08-26 20:27:46 +02:00
parent b5b2bd2193 ede29bdf1b
commit e6b4aae714
21 changed files with 51 additions and 629 deletions
@@ -1,36 +1,24 @@
 # MatrixRTC modes

 Element Call is in the middle of a transition of how a call session is
-represented and how participants pick an SFU:
+represented: from room _state_ events (`org.matrix.msc3401.call.member`) to
+_sticky_ events
+([MSC4354](https://github.com/matrix-org/matrix-spec-proposals/pull/4354)),
+which are a much better fit for the short lived, per-device nature of call
+memberships.

- **Membership events**: from room _state_ events
-  (`org.matrix.msc3401.call.member`) to _sticky_ events
-  ([MSC4354](https://github.com/matrix-org/matrix-spec-proposals/pull/4354)),
-  which are a much better fit for the short lived, per-device nature of call
-  memberships.
- **SFU selection**: from "everyone connects to the SFU of the oldest member" to
-  **multi SFU**, where each participant uses its own homeserver's SFU and the
-  SFUs interconnect.
-
-Not every homeserver supports sticky events yet. Multi SFU is supported on all current (August 2026)
-element call clients. The three MatrixRTC modes are the steps of that transition,
-so a deployment can pick the newest one its homeserver and its user base can
-handle.
+Not every homeserver supports sticky events yet. The two MatrixRTC modes
+controls whether Element Call uses them.

 ## The modes

 | Mode            | Membership events | SFU selection | JWT endpoint                 |
 | --------------- | ----------------- | ------------- | ---------------------------- |
-| `legacy`        | state events      | oldest member | legacy                       |
 | `compatibility` | state events      | multi SFU     | legacy                       |
 | `matrix_2_0`    | sticky events     | multi SFU     | Matrix 2.0 (hashed identity) |

-**`legacy`** — the lowest common denominator. Use it if calls need to work with
-Element Call clients older than v0.17.0, which cannot handle multi SFU calls. (unused)
-
-**`compatibility`** — multi SFU, but still state events. Use it when all Element
-Call clients are v0.17.0 or later but the homeserver does not support sticky
-events. This is the default. (default)
+**`compatibility`** — multi SFU, but still state events. Use it when the
+homeserver does not support sticky events. This is the default.

 **`matrix_2_0`** — the target state. Requires a homeserver that advertises
 MSC4354 and all clients on v0.17.0 or later. The local membership requests its
@@ -54,7 +42,7 @@ disables the Developer Settings choice:
 }
 ```

-Valid values are `legacy`, `compatibility` and `matrix_2_0`; an invalid value is
+Valid values are `compatibility` and `matrix_2_0`; an invalid value is
 ignored (with a warning) and the user's choice applies. Pinning `matrix_2_0` on a
 homeserver without sticky event support makes joining fail with a "sticky events
 required" error.
@@ -80,10 +80,6 @@
        "description": "Compatible with homeservers that do not support sticky events (but all other EC clients are v0.17.0 or later)",
        "label": "Compatibility: state events & multi SFU"
      },
-      "Legacy": {
-        "description": "Compatible with old versions of EC that do not support multi SFU",
-        "label": "Legacy: state events & oldest membership SFU"
-      },
      "Matrix_2_0": {
        "description": "Compatible only with homservers supporting sticky events and all EC clients v0.17.0 or later",
        "label": "Matrix 2.0: sticky events & multi SFU"
@@ -101,9 +101,7 @@ async function setRtcModeFromSettings(

  // Move to Developer tab now
  await page.getByRole("tab", { name: "Developer" }).click();
-  if (mode == "legacy") {
-    await page.getByText("Legacy: state events").click();
-  } else if (mode == "2_0") {
+  if (mode == "2_0") {
    await page.getByText("Matrix 2.0").click();
  } else {
    // compat
@@ -12,9 +12,7 @@ import { HOST1, HOST2, type RtcMode, TestHelpers } from "./test-helpers";

 const modePairs: [RtcMode, RtcMode][] = [
  ["compat", "compat"],
-  ["legacy", "legacy"],
-  ["legacy", "compat"],
-  ["compat", "legacy"],
+  // TODO: Compatibility + Matrix 2.0?
 ];

 modePairs.forEach(([rtcMode1, rtcMode2]) => {
@@ -1,85 +0,0 @@
-/*
-Copyright 2026 Element Creations Ltd.
-
-SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
-Please see LICENSE in the repository root for full details.
-*/
-
-import { expect, test } from "@playwright/test";
-
-import { widgetTest } from "../fixtures/widget-user";
-import { HOST1, HOST2, TestHelpers } from "./test-helpers";
-
-widgetTest(
-  "Bug new joiner was not publishing on correct SFU",
-  async ({ addUser, browserName }) => {
-    test.skip(
-      browserName === "firefox",
-      "This is a bug in the old widget, not a browser problem.",
-    );
-
-    test.slow();
-
-    // 2 users in federation
-    const florian = await addUser("floriant", HOST1);
-    const timo = await addUser("timo", HOST2);
-
-    // Florian creates a room and invites Timo to it
-    const roomName = "Call Room";
-    await TestHelpers.createRoom(roomName, florian.page, [timo.mxId]);
-
-    // Timo joins the room
-    await TestHelpers.acceptRoomInvite(roomName, timo.page);
-
-    // Ensure we are in legacy mode (should be the default)
-    await TestHelpers.openWidgetSetEmbeddedElementCallRtcModeCloseWidget(
-      florian.page,
-      "legacy",
-    );
-    await TestHelpers.openWidgetSetEmbeddedElementCallRtcModeCloseWidget(
-      timo.page,
-      "legacy",
-    );
-
-    // Let timo create a call
-    await TestHelpers.startCallInCurrentRoom(timo.page, false);
-    await TestHelpers.joinCallFromLobby(timo.page);
-
-    // We want to simulate that the oldest membership authentication is way slower than
-    // the preffered auth.
-    // In this setup, timo advertised$ transport will be it's own, and the active will be the one from florian
-    await florian.page.route(
-      "**/matrix-rtc.othersite.m.localhost/livekit/jwt/**",
-      async (route) => {
-        await new Promise((resolve) => setTimeout(resolve, 2000)); // 5 second delay
-        await route.continue();
-      },
-    );
-
-    // Florian joins the call
-    await expect(florian.page.getByTestId("join-call-button")).toBeVisible();
-    await florian.page.getByTestId("join-call-button").click();
-    await TestHelpers.joinCallFromLobby(florian.page);
-
-    await florian.page.waitForTimeout(3000);
-    await timo.page.waitForTimeout(3000);
-
-    // We should see 2 video tiles everywhere now
-    for (const user of [timo, florian]) {
-      const frame = user.page
-        .locator('iframe[title="Element Call"]')
-        .contentFrame();
-      await expect(frame.getByTestId("videoTile")).toHaveCount(2);
-
-      // No one should be waiting for media
-      await expect(frame.getByText("Waiting for media...")).not.toBeVisible();
-
-      // There should be 2 video elements, visible and autoplaying
-      await expect(frame.locator("video")).toHaveCount(2, {
-        timeout: 10000,
-      });
-
-      await TestHelpers.expectVisibleVideoCount(frame, 2);
-    }
-  },
-);
@@ -1,91 +0,0 @@
-/*
-Copyright 2026 Element Creations Ltd.
-
-SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
-Please see LICENSE in the repository root for full details.
-*/
-
-import { expect, test } from "@playwright/test";
-
-import { widgetTest } from "../fixtures/widget-user";
-import { HOST1, HOST2, TestHelpers } from "./test-helpers";
-
-// ## Issue
-// This test reproduces an issue with the publisher.
-// When switching local focus, we need to recreate the publisher.
-// This failed because of a dead lock in the old publishers destruction.
-//
-// There are numerus ways to enforece this situation:
-//  - oldest member swap (manually set the oldest member focus and leave with the prev oldest member)
-//    This almost never happens in the real worls since clients will set their preferredFoci list to what the oldest member is.
-//  - switch from oldest member to multi sfu as the NOT the first joiner + the first joiner is on a different sfu than your preferred sfu.
-//
-// This test uses the "switch from oldest member to multi sfu" approach.
-//
-// It is a copy of federated-call.test.ts in the `["legacy", "legacy"]` setup,
-// which once connected will make the second user switch to multi sfu.
-widgetTest(
-  `Test swapping publisher from ${HOST1} to ${HOST2}`,
-  async ({ addUser, browserName }) => {
-    test.slow();
-    test.skip(
-      browserName === "firefox",
-      "The is test is not working on firefox CI environment. No mic/audio device inputs so cam/mic are disabled",
-    );
-
-    const florian = await addUser("floriant", HOST1);
-    const timo = await addUser("timo", HOST2);
-
-    const roomName = "Call Room";
-
-    await TestHelpers.createRoom(roomName, florian.page, [timo.mxId]);
-
-    await TestHelpers.acceptRoomInvite(roomName, timo.page);
-
-    await florian.page.pause();
-
-    await TestHelpers.openWidgetSetEmbeddedElementCallRtcModeCloseWidget(
-      florian.page,
-      "legacy",
-    );
-    await TestHelpers.openWidgetSetEmbeddedElementCallRtcModeCloseWidget(
-      timo.page,
-      "legacy",
-    );
-
-    await TestHelpers.startCallInCurrentRoom(florian.page, false);
-    await TestHelpers.joinCallFromLobby(florian.page);
-
-    // timo joins
-    await TestHelpers.joinCallInCurrentRoom(timo.page);
-
-    // We should see 2 video tiles everywhere now
-    for (const user of [timo, florian]) {
-      const frame = user.page
-        .locator('iframe[title="Element Call"]')
-        .contentFrame();
-      await expect(frame.getByTestId("videoTile")).toHaveCount(2);
-
-      // Wait for "Waiting for media..." to disappear (with timeout)
-      await expect(frame.getByText("Waiting for media...")).not.toBeVisible({
-        timeout: 10000, // Maximum time to wait
-      });
-
-      // There should be 2 video elements, visible and autoplaying
-      await expect(frame.locator("video")).toHaveCount(2, {
-        timeout: 10000,
-      });
-
-      await TestHelpers.expectVisibleVideoCount(frame, 2);
-    }
-
-    // now we switch the mode for timo (second joiner on multi-sfu HOST2 but currently HOST1)
-    await TestHelpers.setEmbeddedElementCallRtcMode(timo.page, "compat");
-    await timo.page.waitForTimeout(3000);
-
-    await TestHelpers.expectVisibleVideoCount(
-      timo.page.locator('iframe[title="Element Call"]').contentFrame(),
-      2,
-    );
-  },
-);
@@ -21,7 +21,7 @@ const PASSWORD = "foobarbaz1!";
 export const HOST1 = "https://app.m.localhost/#/welcome";
 export const HOST2 = "https://app.othersite.m.localhost/#/welcome";

-export type RtcMode = "legacy" | "compat" | "2_0";
+export type RtcMode = "compat" | "2_0";

 export class TestHelpers {
  public static async startCallInCurrentRoom(
@@ -309,9 +309,7 @@ export class TestHelpers {

    // Move to Developer tab now
    await iframe.getByRole("tab", { name: "Developer" }).click();
-    if (mode == "legacy") {
-      await iframe.getByText("Legacy: state events").click();
-    } else if (mode == "2_0") {
+    if (mode == "2_0") {
      await iframe.getByText("Matrix 2.0").click();
    } else {
      // compat
@@ -12,9 +12,7 @@ Please see LICENSE in the repository root for full details.
 * Settings, or pinned for a deployment via `matrix_rtc_mode` in config.json.
 */
 export enum MatrixRTCMode {
-  /** Legacy single-SFU + user-keyed memberships + legacy JWT endpoint. */
-  Legacy = "legacy",
-  /** Multi-SFU transport, legacy JWT endpoint, no sticky events. */
+  /** Multi-SFU transport, legacy JWT endpoint, state events. */
  Compatibility = "compatibility",
  /**
   * Multi-SFU transport with:
@@ -317,19 +317,15 @@ describe("DeveloperSettingsTab", () => {

  describe("matrix rtc mode", () => {
    afterEach(() => {
-      matrixRTCModeSetting.setValue(MatrixRTCMode.Legacy);
+      matrixRTCModeSetting.setValue(MatrixRTCMode.Compatibility);
      vi.restoreAllMocks();
    });

    function getModeRadios(): {
-      legacy: HTMLInputElement;
      compatibility: HTMLInputElement;
      matrix20: HTMLInputElement;
    } {
      return {
-        legacy: screen.getByDisplayValue(
-          MatrixRTCMode.Legacy,
-        ) as HTMLInputElement,
        compatibility: screen.getByDisplayValue(
          MatrixRTCMode.Compatibility,
        ) as HTMLInputElement,
@@ -359,27 +355,21 @@ describe("DeveloperSettingsTab", () => {

      const radios = getModeRadios();
      expect(radios.compatibility).toBeChecked();
-      expect(radios.legacy).not.toBeChecked();
      expect(radios.matrix20).not.toBeChecked();
      // None are disabled by config; only Matrix_2_0 may be disabled by sticky-events support.
-      expect(radios.legacy).not.toBeDisabled();
      expect(radios.compatibility).not.toBeDisabled();
    });

-    it.each([
-      MatrixRTCMode.Legacy,
-      MatrixRTCMode.Compatibility,
-      MatrixRTCMode.Matrix_2_0,
-    ])(
+    it.each([MatrixRTCMode.Compatibility, MatrixRTCMode.Matrix_2_0])(
      "disables all radios and shows the config value (%s) as checked when matrix_rtc_mode is set",
      async (configMode) => {
        mockConfig({ matrix_rtc_mode: configMode });
        // Local setting is intentionally different from the config value to
        // prove config wins.
        matrixRTCModeSetting.setValue(
-          configMode === MatrixRTCMode.Legacy
-            ? MatrixRTCMode.Compatibility
-            : MatrixRTCMode.Legacy,
+          configMode === MatrixRTCMode.Compatibility
+            ? MatrixRTCMode.Matrix_2_0
+            : MatrixRTCMode.Compatibility,
        );
        const client = createMockMatrixClient();

@@ -397,13 +387,11 @@ describe("DeveloperSettingsTab", () => {
        );

        const radios = getModeRadios();
-        expect(radios.legacy).toBeDisabled();
        expect(radios.compatibility).toBeDisabled();
        expect(radios.matrix20).toBeDisabled();

        const checkedValue = (
          {
-            [MatrixRTCMode.Legacy]: radios.legacy,
            [MatrixRTCMode.Compatibility]: radios.compatibility,
            [MatrixRTCMode.Matrix_2_0]: radios.matrix20,
          } as const
@@ -520,22 +520,6 @@ export const DeveloperSettingsTab: FC<Props> = ({
      </Heading>
      {matrixRTCModeForced && <p>Your deployment overrides the mode.</p>}
      <Form>
-        <InlineField
-          name={matrixRTCModeRadioGroup}
-          control={
-            <RadioControl
-              checked={effectiveMatrixRTCMode === MatrixRTCMode.Legacy}
-              value={MatrixRTCMode.Legacy}
-              disabled={matrixRTCModeForced}
-              onChange={onMatrixRTCModeChange}
-            />
-          }
-        >
-          <Label>{t("developer_mode.matrixRTCMode.Legacy.label")}</Label>
-          <HelpMessage>
-            {t("developer_mode.matrixRTCMode.Legacy.description")}
-          </HelpMessage>
-        </InlineField>
        <InlineField
          name={matrixRTCModeRadioGroup}
          control={
@@ -285,50 +285,10 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
          class="_container_1ug7n_10"
        >
          <input
-            aria-describedby="radix-_r_a_ radix-_r_c_ radix-_r_e_"
-            class="_input_1ug7n_18"
-            id="radix-_r_9_"
-            name="_r_0_"
-            title=""
-            type="radio"
-            value="legacy"
-          />
-          <div
-            class="_ui_1ug7n_19"
-          />
-        </div>
-      </div>
-      <div
-        class="_inline-field-body_1o4d9_39"
-      >
-        <label
-          class="_label_1o4d9_60"
-          for="radix-_r_9_"
-        >
-          Legacy: state events & oldest membership SFU
-        </label>
-        <span
-          class="_message_1o4d9_86 _help-message_1o4d9_92"
-          id="radix-_r_a_"
-        >
-          Compatible with old versions of EC that do not support multi SFU
-        </span>
-      </div>
-    </div>
-    <div
-      class="_inline-field_1o4d9_33"
-    >
-      <div
-        class="_inline-field-control_1o4d9_45"
-      >
-        <div
-          class="_container_1ug7n_10"
-        >
-          <input
-            aria-describedby="radix-_r_a_ radix-_r_c_ radix-_r_e_"
+            aria-describedby="radix-_r_a_ radix-_r_c_"
            checked=""
            class="_input_1ug7n_18"
-            id="radix-_r_b_"
+            id="radix-_r_9_"
            name="_r_0_"
            title=""
            type="radio"
@@ -344,13 +304,13 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      >
        <label
          class="_label_1o4d9_60"
-          for="radix-_r_b_"
+          for="radix-_r_9_"
        >
          Compatibility: state events & multi SFU
        </label>
        <span
          class="_message_1o4d9_86 _help-message_1o4d9_92"
-          id="radix-_r_c_"
+          id="radix-_r_a_"
        >
          Compatible with homeservers that do not support sticky events (but all other EC clients are v0.17.0 or later)
        </span>
@@ -366,9 +326,9 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
          class="_container_1ug7n_10"
        >
          <input
-            aria-describedby="radix-_r_a_ radix-_r_c_ radix-_r_e_"
+            aria-describedby="radix-_r_a_ radix-_r_c_"
            class="_input_1ug7n_18"
-            id="radix-_r_d_"
+            id="radix-_r_b_"
            name="_r_0_"
            title=""
            type="radio"
@@ -384,13 +344,13 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      >
        <label
          class="_label_1o4d9_60"
-          for="radix-_r_d_"
+          for="radix-_r_b_"
        >
          Matrix 2.0: sticky events & multi SFU
        </label>
        <span
          class="_message_1o4d9_86 _help-message_1o4d9_92"
-          id="radix-_r_e_"
+          id="radix-_r_c_"
        >
          Compatible only with homservers supporting sticky events and all EC clients v0.17.0 or later
        </span>
@@ -491,7 +451,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      class="_field_1bd8c0 _checkboxField_1bd8c0"
    >
      <input
-        aria-describedby="_r_k_"
+        aria-describedby="_r_i_"
        id="cameraToggle"
        type="checkbox"
      />
@@ -521,7 +481,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      </label>
      <p
        class="_description_1bd8c0"
-        id="_r_k_"
+        id="_r_i_"
      >
        Configure resolution, framerate, bitrate, and codec for camera video. Changes apply on next call join.
      </p>
@@ -543,7 +503,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      class="_field_1bd8c0 _checkboxField_1bd8c0"
    >
      <input
-        aria-describedby="_r_l_"
+        aria-describedby="_r_j_"
        id="screenShareToggle"
        type="checkbox"
      />
@@ -573,7 +533,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      </label>
      <p
        class="_description_1bd8c0"
-        id="_r_l_"
+        id="_r_j_"
      >
        Configure resolution, framerate, bitrate, and codec for screen sharing
      </p>
@@ -598,7 +558,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      class="_field_1bd8c0 _checkboxField_1bd8c0"
    >
      <input
-        aria-describedby="_r_m_"
+        aria-describedby="_r_k_"
        checked=""
        id="echoCancellation"
        type="checkbox"
@@ -636,7 +596,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      class="_field_1bd8c0 _checkboxField_1bd8c0"
    >
      <input
-        aria-describedby="_r_n_"
+        aria-describedby="_r_l_"
        checked=""
        id="noiseSuppression"
        type="checkbox"
@@ -674,7 +634,7 @@ exports[`DeveloperSettingsTab > renders and matches snapshot 1`] = `
      class="_field_1bd8c0 _checkboxField_1bd8c0"
    >
      <input
-        aria-describedby="_r_o_"
+        aria-describedby="_r_m_"
        checked=""
        id="autoGainControl"
        type="checkbox"
@@ -258,11 +258,9 @@ function mockRingEvent(
  } as unknown as { event_id: string } & IRTCNotificationContent;
 }

-describe.each([
-  [MatrixRTCMode.Legacy],
-  [MatrixRTCMode.Compatibility],
-  [MatrixRTCMode.Matrix_2_0],
-])("CallViewModel (%s mode)", (mode) => {
+const modes = [[MatrixRTCMode.Compatibility], [MatrixRTCMode.Matrix_2_0]];
+
+describe.each(modes)("CallViewModel (%s mode)", (mode) => {
  const withCallViewModel = withCallViewModelInMode(mode);

  test("participants are retained during a focus switch", () => {
@@ -441,7 +441,7 @@ export function createCallViewModel$(
  const matrixRTCMode$ =
    configMatrixRTCMode !== undefined
      ? constant(configMatrixRTCMode)
-      : (options.matrixRTCMode$ ?? constant(MatrixRTCMode.Legacy));
+      : (options.matrixRTCMode$ ?? constant(MatrixRTCMode.Compatibility));

  // Each hbar seperates a block of input variables required for the CallViewModel to function.
  // The outputs of this block is written under the hbar.
@@ -503,7 +503,6 @@ export function createCallViewModel$(
              mode === MatrixRTCMode.Matrix_2_0
                ? JwtEndpointVersion.Matrix_2_0
                : JwtEndpointVersion.Legacy,
-            useOldestMember: mode === MatrixRTCMode.Legacy,
          }),
      ),
    ),
@@ -59,7 +59,7 @@ import {

 initializeWidget();

-const MATRIX_RTC_MODE = MatrixRTCMode.Legacy;
+const MATRIX_RTC_MODE = MatrixRTCMode.Compatibility;
 const getUrlParams = vi.hoisted(() => vi.fn(() => ({})));
 vi.mock("../../../UrlParams", () => ({ getUrlParams }));
 vi.mock("@livekit/components-core", () => ({
@@ -71,12 +71,6 @@ vi.mock("@livekit/components-core", () => ({
 describe("LocalMembership", () => {
  describe("enterRTCSession", () => {
    it("It joins the correct Session", () => {
-      const focusFromOlderMembership = {
-        type: "livekit",
-        livekit_service_url: "http://my-oldest-member-service-url.com",
-        livekit_alias: "my-oldest-member-service-alias",
-      };
-
      mockConfig({
        livekit: { livekit_service_url: "http://my-default-service-url.com" },
      });
@@ -95,10 +89,6 @@ describe("LocalMembership", () => {
          },
        },
        memberships: [],
-        getFocusInUse: vi.fn().mockReturnValue(focusFromOlderMembership),
-        getOldestMembership: vi.fn().mockReturnValue({
-          getPreferredFoci: vi.fn().mockReturnValue([focusFromOlderMembership]),
-        }),
        joinRTCSession: vi.fn(),
      }) as unknown as MatrixRTCSession;

@@ -122,14 +112,12 @@ describe("LocalMembership", () => {
          memberId: "@alice:example.org:DEVICE",
          userId: "@alice:example.org",
        },
-        [
-          {
-            livekit_alias: "roomId",
-            livekit_service_url: "http://my-livekit-service-url.com",
-            type: "livekit",
-          },
-        ],
-        undefined,
+        [],
+        {
+          livekit_alias: "roomId",
+          livekit_service_url: "http://my-livekit-service-url.com",
+          type: "livekit",
+        },
        expect.objectContaining({ manageMediaKeys: true }),
      );
    });
@@ -117,7 +117,6 @@ export type LocalMemberState =
    };

 /*
- * - get oldest membership
 * - get transport to use
 * - get openId + jwt token
 * - wait for createTrack() call
@@ -13,7 +13,6 @@ import {
  it,
  type MockedObject,
  vi,
-  type MockInstance,
 } from "vitest";
 import {
  type CallMembership,
@@ -26,7 +25,6 @@ import {
  mockConfig,
  flushPromises,
  ownMemberMock,
-  mockRtcMembership,
  testScope,
 } from "../../../utils/test";
 import {
@@ -35,7 +33,7 @@ import {
  type LocalTransportWithSFUConfig,
 } from "./LocalTransport";
 import { constant } from "../../Behavior";
-import { Epoch, ObservableScope, trackEpoch } from "../../ObservableScope";
+import { Epoch, ObservableScope } from "../../ObservableScope";
 import {
  MatrixRTCTransportMissingError,
  FailToGetOpenIdToken,
@@ -58,7 +56,6 @@ describe("LocalTransport", () => {
    const { advertised$, active$ } = createLocalTransport$({
      scope: testScope(),
      roomId: "!room:example.org",
-      useOldestMember: false,
      memberships$: constant(new Epoch<CallMembership[]>([])),
      client: {
        // eslint-disable-next-line @typescript-eslint/naming-convention
@@ -101,7 +98,6 @@ describe("LocalTransport", () => {
    const { advertised$, active$ } = createLocalTransport$({
      scope,
      roomId: "!example_room_id",
-      useOldestMember: false,
      memberships$: constant(new Epoch<CallMembership[]>([])),
      client: {
        baseUrl: "https://example.org",
@@ -144,7 +140,6 @@ describe("LocalTransport", () => {
    const { advertised$, active$ } = createLocalTransport$({
      scope: testScope(),
      roomId: "!room:example.org",
-      useOldestMember: false,
      memberships$: constant(new Epoch<CallMembership[]>([])),
      client: {
        // eslint-disable-next-line @typescript-eslint/naming-convention
@@ -185,127 +180,6 @@ describe("LocalTransport", () => {
    });
  });

-  describe("oldest member mode", () => {
-    const aliceTransport: LivekitTransportConfig = {
-      type: "livekit",
-      livekit_service_url: "https://alice.example.org",
-    };
-    const bobTransport: LivekitTransportConfig = {
-      type: "livekit",
-      livekit_service_url: "https://bob.example.org",
-    };
-    const aliceMembership = mockRtcMembership("@alice:example.org", "AAA", {
-      fociPreferred: [aliceTransport],
-    });
-    const bobMembership = mockRtcMembership("@bob:example.org", "BBB", {
-      fociPreferred: [bobTransport],
-    });
-
-    let openIdSpy: MockInstance<(typeof openIDSFU)["getSFUConfigWithOpenID"]>;
-    beforeEach(() => {
-      openIdSpy = vi
-        .spyOn(openIDSFU, "getSFUConfigWithOpenID")
-        .mockResolvedValue(openIdResponse);
-    });
-
-    it("updates active transport when oldest member changes", async () => {
-      // Initially, Alice is the only member
-      const memberships$ = new BehaviorSubject([aliceMembership]);
-
-      const scope = testScope();
-      const { advertised$, active$ } = createLocalTransport$({
-        scope,
-        roomId: "!example_room_id",
-        useOldestMember: true,
-        memberships$: scope.behavior(memberships$.pipe(trackEpoch())),
-        client: {
-          getDomain: () => "example.org",
-          // eslint-disable-next-line @typescript-eslint/naming-convention
-          _unstable_getRTCTransports: async () => Promise.resolve([]),
-          getOpenIdToken: vi.fn(),
-          getDeviceId: vi.fn(),
-          baseUrl: "https://example.org",
-        },
-        ownMembershipIdentity: ownMemberMock,
-        forceJwtEndpoint: JwtEndpointVersion.Legacy,
-        delayId$: constant("delay_id_mock"),
-      });
-
-      expect(active$.value).toBe(null);
-      await flushPromises();
-      // SFU config should've been fetched
-      expect(openIdSpy).toHaveBeenCalled();
-      // Alice's transport should be active and advertised
-      expect(active$.value?.transport).toStrictEqual(aliceTransport);
-      expect(advertised$.value).toStrictEqual(aliceTransport);
-
-      // Now Bob joins the call, but Alice is still the oldest member
-      openIdSpy.mockClear();
-      memberships$.next([aliceMembership, bobMembership]);
-      await flushPromises();
-      // No new SFU config should've been fetched
-      expect(openIdSpy).not.toHaveBeenCalled();
-      // Alice's transport should still be active and advertised
-      expect(active$.value?.transport).toStrictEqual(aliceTransport);
-      expect(advertised$.value).toStrictEqual(aliceTransport);
-
-      // Now Bob takes Alice's place as the oldest member
-      openIdSpy.mockClear();
-      memberships$.next([bobMembership, aliceMembership]);
-      // Active transport should reset to null until we have Bob's SFU config
-      expect(active$.value).toStrictEqual(null);
-      await flushPromises();
-      // Bob's SFU config should've been fetched
-      expect(openIdSpy).toHaveBeenCalled();
-      // Bob's transport should be active, but Alice's should remain advertised
-      // (since we don't want the change in oldest member to cause a wave of new
-      // state events)
-      expect(active$.value?.transport).toStrictEqual(bobTransport);
-      expect(advertised$.value).toStrictEqual(aliceTransport);
-    });
-
-    it("advertises preferred transport when no other member exists", async () => {
-      // Initially, there are no members
-      const memberships$ = new BehaviorSubject<CallMembership[]>([]);
-
-      const scope = testScope();
-      const { advertised$, active$ } = createLocalTransport$({
-        scope,
-        roomId: "!example_room_id",
-        useOldestMember: true,
-        memberships$: scope.behavior(memberships$.pipe(trackEpoch())),
-        client: {
-          getDomain: () => "example.org",
-          // eslint-disable-next-line @typescript-eslint/naming-convention
-          _unstable_getRTCTransports: async () =>
-            Promise.resolve([aliceTransport]),
-          getOpenIdToken: vi.fn(),
-          getDeviceId: vi.fn(),
-          baseUrl: "https://example.org",
-        },
-        ownMembershipIdentity: ownMemberMock,
-        forceJwtEndpoint: JwtEndpointVersion.Legacy,
-        delayId$: constant("delay_id_mock"),
-      });
-
-      expect(active$.value).toBe(null);
-      await flushPromises();
-      // Our own preferred transport should be advertised
-      expect(advertised$.value).toStrictEqual(aliceTransport);
-      // No transport should be active however (there is still no oldest member)
-      expect(active$.value).toBe(null);
-
-      // Now Bob joins the call and becomes the oldest member
-      memberships$.next([bobMembership]);
-      await flushPromises();
-      // We should still advertise our own preferred transport (to avoid
-      // unnecessary state changes)
-      expect(advertised$.value).toStrictEqual(aliceTransport);
-      // Bob's transport should become active
-      expect(active$.value?.transport).toBe(bobTransport);
-    });
-  });
-
  type LocalTransportProps = Parameters<typeof createLocalTransport$>[0];

  describe("transport configuration mechanisms", () => {
@@ -320,7 +194,6 @@ describe("LocalTransport", () => {
        ownMembershipIdentity: ownMemberMock,
        scope: testScope(),
        roomId: "!example_room_id",
-        useOldestMember: false,
        forceJwtEndpoint: JwtEndpointVersion.Legacy,
        delayId$: constant(null),
        memberships$: constant(new Epoch<CallMembership[]>([])),
@@ -433,7 +306,6 @@ describe("LocalTransport", () => {
        scope: testScope(),
        ownMembershipIdentity: ownMemberMock,
        roomId: "!example_room_id",
-        useOldestMember: false,
        forceJwtEndpoint: JwtEndpointVersion.Legacy,
        delayId$: constant(null),
        memberships$: constant(new Epoch<CallMembership[]>([])),
@@ -473,7 +345,6 @@ describe("LocalTransport", () => {
      ownMembershipIdentity: ownMemberMock,
      roomId: "!example_room_id",
      // We want multi-sdu
-      useOldestMember: false,
      forceJwtEndpoint: JwtEndpointVersion.Legacy,
      delayId$: delayId$,
      memberships$: constant(new Epoch<CallMembership[]>([])),
@@ -7,23 +7,16 @@ Please see LICENSE in the repository root for full details.

 import {
  type CallMembership,
-  isLivekitTransportConfig,
  type LivekitTransportConfig,
 } from "matrix-js-sdk/lib/matrixrtc";
 import { type MatrixClient } from "matrix-js-sdk";
 import {
-  catchError,
  combineLatest,
  distinctUntilChanged,
-  first,
  from,
  map,
-  merge,
-  type Observable,
  of,
-  startWith,
  switchMap,
-  tap,
 } from "rxjs";
 import { logger as rootLogger, type Logger } from "matrix-js-sdk/lib/logger";
 import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
@@ -47,8 +40,7 @@ import { RtcTransportAutoDiscovery } from "./RtcTransportAutoDiscovery.ts";

 /*
 * It figures out “which LiveKit focus URL/alias the local user should use,”
- * optionally aligning with the oldest member, and ensures the SFU path is primed
- * before advertising that choice.
+ * and ensures the SFU path is primed before advertising that choice.
 */
 interface Props {
  scope: ObservableScope;
@@ -61,7 +53,6 @@ interface Props {
    OpenIDClientParts;
  // Used by the jwt service to create the livekit room and compute the livekit alias.
  roomId: string;
-  useOldestMember: boolean;
  forceJwtEndpoint: JwtEndpointVersion;
  delayId$: Behavior<string | null>;
 }
@@ -119,8 +110,6 @@ export interface LocalTransport {
 /**
 * Connects to the JWT service and determines the transports that the local member should use.
 *
- * @prop useOldestMember Whether to use the same transport as the oldest member.
- * This will only update once the first oldest member appears. Will not recompute if the oldest member leaves.
 * @prop useOldJwtEndpoint Whether to set forceOldJwtEndpoint on the returned transport and to use the old JWT endpoint.
 * This is used when the connection manager needs to know if it has to use the legacy endpoint which implies a string concatenated rtcBackendIdentity.
 * (which is expected for non sticky event based rtc member events)
@@ -133,18 +122,10 @@ export const createLocalTransport$ = ({
  ownMembershipIdentity,
  client,
  roomId,
-  useOldestMember,
  forceJwtEndpoint,
  delayId$,
 }: Props): LocalTransport => {
  const logger = rootLogger.getChild("[LocalTransport]");
-  // The LiveKit transport in use by the oldest RTC membership. `null` when the
-  // oldest member has no such transport.
-  const oldestMemberTransport$ = observerOldestMembership$(
-    scope,
-    memberships$,
-    logger,
-  );

  const transportDiscovery = new RtcTransportAutoDiscovery({
    client: client,
@@ -203,19 +184,6 @@ export const createLocalTransport$ = ({
    }),
  );

-  if (useOldestMember) {
-    return observeLocalTransportForOldestMembership(
-      scope,
-      oldestMemberTransport$,
-      preferredTransport$,
-      client,
-      ownMembershipIdentity,
-      roomId,
-      logger,
-    );
-  }
-
-  // --- Multi-SFU mode ---
  // Always publish on and advertise the preferred transport.
  return {
    advertised$: scope.behavior(
@@ -243,47 +211,6 @@ export const createLocalTransport$ = ({
  };
 };

-/**
- * Observes the oldest member in the room and returns the transport that it uses if it is a livekit transport.
- * @param scope - The observable scope.
- * @param memberships$ - The observable of the call's memberships.'
- */
-function observerOldestMembership$(
-  scope: ObservableScope,
-  memberships$: Behavior<Epoch<CallMembership[]>>,
-  logger: Logger,
-): Behavior<LivekitTransportConfig | null> {
-  return scope.behavior<LivekitTransportConfig | null>(
-    memberships$.pipe(
-      map((memberships) => {
-        const oldestMember = memberships.value[0];
-        if (oldestMember === undefined) {
-          logger.info("Oldest member: not found");
-          return null;
-        }
-        const transport = oldestMember.getTransport(oldestMember);
-        if (transport === undefined) {
-          logger.warn(
-            `Oldest member: ${oldestMember.userId}|${oldestMember.deviceId}|${oldestMember.memberId} has no transport`,
-          );
-          return null;
-        }
-        if (!isLivekitTransportConfig(transport)) {
-          logger.warn(
-            `Oldest member: ${oldestMember.userId}|${oldestMember.deviceId}|${oldestMember.memberId} has invalid transport`,
-          );
-          return null;
-        }
-        logger.info(
-          "Oldest member: ${oldestMember.userId}|${oldestMember.deviceId}|${oldestMember.memberId} has valid transport",
-        );
-        return transport;
-      }),
-      distinctUntilChanged(areLivekitTransportsEqual),
-    ),
-  );
-}
-
 /**
 *  Utility to ensure the user can authenticate with the SFU.
 *  We will call `getSFUConfigWithOpenID` once per transport here as it's our
@@ -331,85 +258,6 @@ async function doOpenIdAndJWTFromUrl(
  };
 }

-function observeLocalTransportForOldestMembership(
-  scope: ObservableScope,
-  oldestMemberTransport$: Behavior<LivekitTransportConfig | null>,
-  preferredTransport$: Observable<LocalTransportWithSFUConfig>,
-  client: Pick<
-    MatrixClient,
-    "getDomain" | "baseUrl" | "_unstable_getRTCTransports"
-  > &
-    OpenIDClientParts,
-  ownMembershipIdentity: CallMembershipIdentityParts,
-  roomId: string,
-  logger: Logger,
-): LocalTransport {
-  // Ensure we can authenticate with the SFU.
-  const authenticatedOldestMemberTransport$ = oldestMemberTransport$.pipe(
-    switchMap((transport) => {
-      // Oldest member not available -we are first- (or invalid SFU config).
-      if (transport === null) return of(null);
-
-      // Whenever there is transport change we want to revert
-      // to no transport while we do the authentication.
-      // So do a from(promise) here to be able to startWith(null)
-      return from(
-        doOpenIdAndJWTFromUrl(
-          transport,
-          JwtEndpointVersion.Legacy,
-          ownMembershipIdentity,
-          roomId,
-          client,
-          undefined,
-          logger,
-        ),
-      ).pipe(
-        catchError((e: unknown) => {
-          logger.error(
-            `Failed to authenticate to transport ${transport.livekit_service_url}`,
-            e,
-          );
-          throw mapAuthErrorToUserFriendlyError(e);
-        }),
-        startWith(null),
-      );
-    }),
-  );
-
-  // --- Oldest member mode ---
-  return {
-    // Never update the transport that we advertise in our membership. Just
-    // take the first valid oldest member or preferred transport that we learn
-    // about, and stick with that. This avoids unnecessary SFU hops and room
-    // state changes.
-    advertised$: scope.behavior(
-      merge(
-        authenticatedOldestMemberTransport$.pipe(
-          map((t) => t?.transport ?? null),
-        ),
-        preferredTransport$.pipe(map((t) => t.transport)),
-      ).pipe(
-        first((t) => t !== null),
-        tap((t) =>
-          logger.info(`Advertise transport: ${t.livekit_service_url}`),
-        ),
-      ),
-      null,
-    ),
-    // Publish on the transport used by the oldest member.
-    active$: scope.behavior(
-      authenticatedOldestMemberTransport$.pipe(
-        tap((t) =>
-          logger.info(
-            `Publish on transport: ${t?.transport.livekit_service_url}`,
-          ),
-        ),
-      ),
-      null,
-    ),
-  };
-}
-
 function mapAuthErrorToUserFriendlyError(e: unknown): Error {
  if (
    e instanceof FailToGetOpenIdToken ||
@@ -36,7 +36,6 @@ import {
  SFURoomCreationRestrictedError,
  UnknownCallError,
 } from "../../../utils/errors.ts";
-import { type JwtEndpointVersion } from "../localMember/LocalTransport.ts";

 export interface ConnectionOpts {
  /**
@@ -44,11 +43,6 @@ export interface ConnectionOpts {
   * On top the local transport will send additional data to the jwt server to use delayed event delegation.
   */
  existingSFUConfig?: SFUConfig;
-  /**
-   * For local connections that use the oldest member pattern. here we have not prefetched the sfuConfig
-   * and hence we need to let the connection do the jwt token fetching.
-   */
-  forceJwtEndpoint?: JwtEndpointVersion;
  /** The identity parts to use on this connection */
  ownMembershipIdentity: CallMembershipIdentityParts;
  /** The media transport to connect to. */
@@ -35,11 +35,7 @@ vi.mock("../widget", () => ({
  },
 }));

-it.each([
-  [MatrixRTCMode.Legacy],
-  [MatrixRTCMode.Compatibility],
-  [MatrixRTCMode.Matrix_2_0],
-])(
+it.each([[MatrixRTCMode.Compatibility], [MatrixRTCMode.Matrix_2_0]])(
  "expect leave when ElementWidgetActions.HangupCall is called (%s mode)",
  async (mode) => {
    const pr = Promise.withResolvers<string>();
@@ -171,7 +171,7 @@ export function getBasicCallViewModelEnvironment(
          setE2EEEnabled: async () => Promise.resolve(),
        }),
      connectionState$: constant(ConnectionState.Connected),
-      matrixRTCMode$: constant(MatrixRTCMode.Legacy),
+      matrixRTCMode$: constant(MatrixRTCMode.Compatibility),
      ...callViewModelOptions,
    },
    handRaisedSubject$,
@@ -237,7 +237,7 @@ export function mockRtcMembership(
      fociPreferred: [exampleTransport],
      focusActive: {
        type: "livekit" as const,
-        focus_selection: "oldest_membership" as const,
+        focus_selection: "multi_sfu" as const,
      },
      callId: "",
      membership: {},
@@ -463,9 +463,6 @@ export class MockRTCSession extends TypedEventEmitter<
    session.reemitEncryptionKeys = vi
      .fn<() => void>()
      .mockReturnValue(undefined);
-    session.getOldestMembership = vi
-      .fn<() => CallMembership | undefined>()
-      .mockReturnValue(this.memberships[0]);

    return session;
  }