diff --git a/type/__matrix_synapse/files/homeserver.yaml.sh b/type/__matrix_synapse/files/homeserver.yaml.sh
index d8e6653..bc8cff0 100755
--- a/type/__matrix_synapse/files/homeserver.yaml.sh
+++ b/type/__matrix_synapse/files/homeserver.yaml.sh
@@ -448,7 +448,7 @@ retention:
   # matter much because Synapse doesn't take it into account yet.
   #
   default_policy:
-    min_lifetime: 1d
+    min_lifetime: ${MESSAGE_RETENTION_POLICY_MIN_LIFETIME:?}
     max_lifetime: ${MESSAGE_RETENTION_POLICY_MAX_LIFETIME:?}
 
   # Retention policy limits. If set, and the state of a room contains a
diff --git a/type/__matrix_synapse/manifest b/type/__matrix_synapse/manifest
index 5a9871d..9e1a07c 100755
--- a/type/__matrix_synapse/manifest
+++ b/type/__matrix_synapse/manifest
@@ -254,7 +254,8 @@ fi
 # Message retention.
 ENABLE_MESSAGE_RETENTION_POLICY=$(get_boolean_for 'enable-message-retention-policy')
 MESSAGE_RETENTION_POLICY_MAX_LIFETIME=$(cat "$__object/parameter/message-max-lifetime")
-export ENABLE_MESSAGE_RETENTION_POLICY MESSAGE_RETENTION_POLICY_MAX_LIFETIME
+MESSAGE_RETENTION_POLICY_MIN_LIFETIME=$MESSAGE_RETENTION_POLICY_MAX_LIFETIME
+export ENABLE_MESSAGE_RETENTION_POLICY MESSAGE_RETENTION_POLICY_MAX_LIFETIME MESSAGE_RETENTION_POLICY_MIN_LIFETIME
 
 # Previews.
 ENABLE_URL_PREVIEW=$(get_boolean_for 'enable-url-preview')