diff --git a/install/elementsynapse-install.sh b/install/elementsynapse-install.sh
index 2d4523589..226b965b3 100644
--- a/install/elementsynapse-install.sh
+++ b/install/elementsynapse-install.sh
@@ -43,6 +43,24 @@ SECRET=$(openssl rand -hex 32)
 ADMIN_PASS="$(openssl rand -base64 18 | cut -c1-13)"
 echo "enable_registration_without_verification: true" >>/etc/matrix-synapse/homeserver.yaml
 echo "registration_shared_secret: ${SECRET}" >>/etc/matrix-synapse/homeserver.yaml
+
+cat <<EOF >>/etc/matrix-synapse/homeserver.yaml
+
+# MatrixRTC / Element Call configuration
+experimental_features:
+  msc3266_enabled: true
+  msc4222_enabled: true
+
+max_event_delay_duration: 24h
+
+rc_message:
+  per_second: 0.5
+  burst_count: 30
+
+rc_delayed_event_mgmt:
+  per_second: 1
+  burst_count: 20
+EOF
 systemctl enable -q --now matrix-synapse
 $STD register_new_matrix_user -a --user admin --password "$ADMIN_PASS" --config /etc/matrix-synapse/homeserver.yaml
 {