From 0443ef55d19bc9ac1e96a4f677b73202748beeb7 Mon Sep 17 00:00:00 2001
From: Robin <robin@robin.town>
Date: Wed, 26 Aug 2026 17:05:38 +0200
Subject: [PATCH] Remove feature_use_device_session_member_events

Support for events with an array of memberships from different devices was removed over a year ago in matrix-js-sdk ffd3c9575e9def576739baf6b1dc329b0db55c0c.
---
 config/config.devenv.json                          |  3 ---
 config/config.sample.json                          |  3 ---
 src/config/ConfigOptions.ts                        | 12 ------------
 src/state/CallViewModel/localMember/LocalMember.ts |  7 +------
 4 files changed, 1 insertion(+), 24 deletions(-)

diff --git a/config/config.devenv.json b/config/config.devenv.json
index df0ff4c18..48602406b 100644
--- a/config/config.devenv.json
+++ b/config/config.devenv.json
@@ -5,9 +5,6 @@
       "server_name": "synapse.m.localhost"
     }
   },
-  "features": {
-    "feature_use_device_session_member_events": true
-  },
   "ssla": "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
   "matrix_rtc_session": {
     "wait_for_key_rotation_ms": 3000,
diff --git a/config/config.sample.json b/config/config.sample.json
index 78f9536da..0baa522e4 100644
--- a/config/config.sample.json
+++ b/config/config.sample.json
@@ -8,9 +8,6 @@
   "livekit": {
     "livekit_service_url": "https://livekit-jwt.mydomain.com"
   },
-  "features": {
-    "feature_use_device_session_member_events": true
-  },
   "ssla": "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
   "matrix_rtc_mode": "compatibility",
   "matrix_rtc_session": {
diff --git a/src/config/ConfigOptions.ts b/src/config/ConfigOptions.ts
index ffe04d69e..de6500b1d 100644
--- a/src/config/ConfigOptions.ts
+++ b/src/config/ConfigOptions.ts
@@ -86,15 +86,6 @@ export interface ConfigOptions {
      * Allow to join group calls without audio and video.
      */
     feature_group_calls_without_video_and_audio?: boolean;
-
-    /**
-     * Send device-specific call session membership state events instead of
-     * legacy user-specific call membership state events.
-     * This setting has no effect when the user joins an active call with
-     * legacy state events. For compatibility, Element Call will always join
-     * active legacy calls with legacy state events.
-     */
-    feature_use_device_session_member_events?: boolean;
   };
 
   /**
@@ -267,9 +258,6 @@ export interface ResolvedConfigOptions extends ConfigOptions {
 }
 
 export const DEFAULT_CONFIG: ResolvedConfigOptions = {
-  features: {
-    feature_use_device_session_member_events: true,
-  },
   sync_disconnect_grace_period_ms: 10000,
   ssla: "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
   media_quality: {
diff --git a/src/state/CallViewModel/localMember/LocalMember.ts b/src/state/CallViewModel/localMember/LocalMember.ts
index fcc8ed0a6..5108b7e3b 100644
--- a/src/state/CallViewModel/localMember/LocalMember.ts
+++ b/src/state/CallViewModel/localMember/LocalMember.ts
@@ -851,9 +851,7 @@ export function enterRTCSession(
   // have started tracking by the time calls start getting created.
   // groupCallOTelMembership?.onJoinCall();
 
-  const { features, matrix_rtc_session: matrixRtcSessionConfig } = Config.get();
-  const useDeviceSessionMemberEvents =
-    features?.feature_use_device_session_member_events;
+  const { matrix_rtc_session: matrixRtcSessionConfig } = Config.get();
   const { sendNotificationType: notificationType, callIntent } = getUrlParams();
   const multiSFU =
     matrixRTCMode === MatrixRTCMode.Compatibility ||
@@ -895,9 +893,6 @@ export function enterRTCSession(
       notificationType,
       callIntent,
       manageMediaKeys: encryptMedia,
-      ...(useDeviceSessionMemberEvents !== undefined && {
-        useLegacyMemberEvents: !useDeviceSessionMemberEvents,
-      }),
       delayedLeaveEventRestartMs:
         matrixRtcSessionConfig?.delayed_leave_event_restart_ms,
       delayedLeaveEventDelayMs: