diff --git a/backend/dev_homeserver-othersite.yaml b/backend/dev_homeserver-othersite.yaml
index 18f986505..4782dbb34 100644
--- a/backend/dev_homeserver-othersite.yaml
+++ b/backend/dev_homeserver-othersite.yaml
@@ -79,4 +79,6 @@ rc_message:
 matrix_rtc:
   transports:
     - type: livekit
-      livekit_service_url: https://matrix-rtc.othersite.m.localhost/livekit/jwt
+      # Omitting livekit_service_url forces usage of the C-S endpoints.
+      # livekit_service_url: https://matrix-rtc.othersite.m.localhost/livekit/jwt
+      url: wss://matrix-rtc.othersite.m.localhost/livekit/sfu
diff --git a/backend/dev_homeserver.yaml b/backend/dev_homeserver.yaml
index e99a50934..9c87ac18e 100644
--- a/backend/dev_homeserver.yaml
+++ b/backend/dev_homeserver.yaml
@@ -79,4 +79,6 @@ rc_message:
 matrix_rtc:
   transports:
     - type: livekit
-      livekit_service_url: https://matrix-rtc.m.localhost/livekit/jwt
+      # Omitting livekit_service_url forces usage of the C-S endpoints.
+      # livekit_service_url: https://matrix-rtc.m.localhost/livekit/jwt
+      url: wss://matrix-rtc.m.localhost/livekit/sfu
diff --git a/docker-compose-dev.yml b/docker-compose-dev.yml
index a767b9916..a1b092c25 100644
--- a/docker-compose-dev.yml
+++ b/docker-compose-dev.yml
@@ -153,8 +153,19 @@ services:
       - ecbackend
 
   element-web:
-    image: ghcr.io/element-hq/element-web:develop
-    pull_policy: always
+    # image: ghcr.io/element-hq/element-web:develop
+    # pull_policy: always
+    # Built from https://github.com/element-hq/element-web/pull/35446 while it
+    # is unmerged.
+    image: element-web:pr-35446
+    pull_policy: build
+    build:
+      context: https://github.com/element-hq/element-web.git#johannes/rtc-cs-widget
+      dockerfile: apps/web/Dockerfile
+      target: element_web
+      args:
+        # The Dockerfile reads the version from .git, which a git context drops by default
+        BUILDKIT_CONTEXT_KEEP_GIT_DIR: 1
     volumes:
       - ./backend/ew.test.config.json:/app/config.json:Z
       # Replaces the Element Call widget bundled in the image with the embedded
@@ -168,8 +179,11 @@ services:
       - ecbackend
 
   element-web-1:
-    image: ghcr.io/element-hq/element-web:develop
-    pull_policy: always
+    # image: ghcr.io/element-hq/element-web:develop
+    # pull_policy: always
+    # The image the element-web service builds
+    image: element-web:pr-35446
+    pull_policy: never
     volumes:
       - ./backend/ew.test.othersite.config.json:/app/config.json:Z
       # Replaces the Element Call widget bundled in the image with the embedded
diff --git a/src/widget.ts b/src/widget.ts
index b35e335bc..761a434bd 100644
--- a/src/widget.ts
+++ b/src/widget.ts
@@ -179,6 +179,8 @@ export const initializeWidget = (
           updateDelayedEvents: true,
           sendSticky: true,
           receiveSticky: true,
+          rtcLivekitGetToken: true,
+          rtcLivekitDelegateDelayedLeave: true,
         },
         roomId,
         {