diff --git a/roles/custom/matrix-synapse/defaults/main.yml b/roles/custom/matrix-synapse/defaults/main.yml
index 113edb498..8e270a749 100644
--- a/roles/custom/matrix-synapse/defaults/main.yml
+++ b/roles/custom/matrix-synapse/defaults/main.yml
@@ -1275,6 +1275,14 @@ 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 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.
+# This is required by Element Call to track room state reliably.
+#
+# See https://github.com/matrix-org/matrix-spec-proposals/pull/4222
+matrix_synapse_experimental_features_msc4222_enabled: false
+
 # Enable this to activate the REST auth password provider module.
 # See: https://github.com/ma1uta/matrix-synapse-rest-password-provider
 matrix_synapse_ext_password_provider_rest_auth_enabled: false
diff --git a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2 b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
index ebdf323d8..9675bb245 100644
--- a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
+++ b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
@@ -2990,6 +2990,9 @@ experimental_features:
   {% if matrix_synapse_experimental_features_msc4140_enabled %}
   msc4140_enabled: true
   {% endif %}
+  {% if matrix_synapse_experimental_features_msc4222_enabled %}
+  msc4222_enabled: true
+  {% endif %}
 
 {% if matrix_synapse_experimental_features_msc4140_enabled %}
 max_event_delay_duration: {{ matrix_synapse_max_event_delay_duration | to_json }}