From 63c4fffe652851730721d73439a0ca84eb397684 Mon Sep 17 00:00:00 2001
From: Slavi Pantaleev <slavi@devture.com>
Date: Mon, 23 Mar 2026 17:21:38 +0200
Subject: [PATCH] Add Synapse support for MSC4143

---
 roles/custom/matrix-synapse/defaults/main.yml              | 7 +++++++
 .../matrix-synapse/templates/synapse/homeserver.yaml.j2    | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/roles/custom/matrix-synapse/defaults/main.yml b/roles/custom/matrix-synapse/defaults/main.yml
index 0a240a81f..e28bd442c 100644
--- a/roles/custom/matrix-synapse/defaults/main.yml
+++ b/roles/custom/matrix-synapse/defaults/main.yml
@@ -1430,6 +1430,13 @@ matrix_synapse_experimental_features_msc4140_enabled: false
 # See `matrix_synapse_experimental_features_msc4140_enabled`.
 matrix_synapse_max_event_delay_duration: 24h
 
+# Controls whether to enable the MSC4143 experimental feature (RTC transports).
+#
+# This is used by MatrixRTC clients to discover the unstable RTC transports API.
+#
+# See https://github.com/matrix-org/matrix-spec-proposals/pull/4143
+matrix_synapse_experimental_features_msc4143_enabled: false
+
 # Controls whether to enable the MSC4222 experimental feature (adding `state_after` to sync v2).
 #
 # Allow clients to opt-in to a change of the sync v2 API that allows them to correctly track the state of the room.
diff --git a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2 b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
index c734f88bc..25585fafd 100644
--- a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
+++ b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
@@ -3010,6 +3010,9 @@ experimental_features:
   {% if matrix_synapse_experimental_features_msc4140_enabled %}
   msc4140_enabled: true
   {% endif %}
+  {% if matrix_synapse_experimental_features_msc4143_enabled %}
+  msc4143_enabled: true
+  {% endif %}
   {% if matrix_synapse_experimental_features_msc4222_enabled %}
   msc4222_enabled: true
   {% endif %}