diff --git a/type/__matrix_synapse/files/homeserver.yaml.sh b/type/__matrix_synapse/files/homeserver.yaml.sh
index f0df206..6437f1b 100755
--- a/type/__matrix_synapse/files/homeserver.yaml.sh
+++ b/type/__matrix_synapse/files/homeserver.yaml.sh
@@ -1334,7 +1334,7 @@ fi
 cat << EOF
 # Enable 3PIDs lookup requests to identity servers from this server.
 #
-#enable_3pid_lookup: true
+enable_3pid_lookup: ${ENABLE_3PID_LOOKUPS:?}
 
 # If set, allows registration of standard or admin accounts by anyone who
 # has the shared secret, even if registration is otherwise disabled.
diff --git a/type/__matrix_synapse/man.rst b/type/__matrix_synapse/man.rst
index 125a9ac..dbcc993 100644
--- a/type/__matrix_synapse/man.rst
+++ b/type/__matrix_synapse/man.rst
@@ -239,6 +239,9 @@ allow-public-rooms-without-auth
 enable-server-notices
   Enable the server notices room.
 
+enable-3pid-lookups
+  Enable 3PIDs lookup requests to identity servers from this server.
+
 allow-guest-access
   Allows users to register as guests without a password/email/etc, and
   participate in rooms hosted on this server which have been made accessible
diff --git a/type/__matrix_synapse/manifest b/type/__matrix_synapse/manifest
index 078d395..70232a8 100755
--- a/type/__matrix_synapse/manifest
+++ b/type/__matrix_synapse/manifest
@@ -37,7 +37,7 @@ case "$os" in
 			--uri https://packages.matrix.org/debian/ \
 			--component main
 		package_req="__apt_source/matrix-org"
-		;;
+	;;
 	alpine)
 		synapse_user=synapse
 		synapse_pkg=synapse
@@ -96,7 +96,7 @@ export SERVER_NAME BASE_URL REPORT_STATS MAX_UPLOAD_SIZE EXPOSE_METRICS \
 	WEB_CLIENT_URL ROOM_ENCRYPTION_POLICY BIND_ADDRESSES
 
 if [ -f "$__object/parameter/enable-server-notices" ]; then
-    export ENABLE_SERVER_NOTICES=1
+	export ENABLE_SERVER_NOTICES=1
 fi
 
 # TLS.
@@ -178,51 +178,57 @@ if [ -f "$__object/parameter/registration-shared-secret" ]; then
 fi
 
 if [ -f "$__object/parameter/registration-requires-email" ]; then
-    export REGISTRATION_REQUIRES_EMAIL=1
+	export REGISTRATION_REQUIRES_EMAIL=1
 fi
 
 if [ -f "$__object/parameter/auto-join-room" ]; then
-    AUTO_JOIN_ROOMS="$(cat "$__object/parameter/auto-join-room")"
-    export AUTO_JOIN_ROOMS
+	AUTO_JOIN_ROOMS="$(cat "$__object/parameter/auto-join-room")"
+	export AUTO_JOIN_ROOMS
 fi
 
 if [ -f "$__object/parameter/registration-allows-email-pattern" ]; then
-    RESGISTRATION_ALLOWS_EMAIL_PATTERN=$(cat "$__object/parameter/registration-allows-email-pattern")
-    export RESGISTRATION_ALLOWS_EMAIL_PATTERN
+	RESGISTRATION_ALLOWS_EMAIL_PATTERN=$(cat "$__object/parameter/registration-allows-email-pattern")
+	export RESGISTRATION_ALLOWS_EMAIL_PATTERN
 fi
 
 if [ -f "$__object/parameter/saml2-idp-metadata-url" ]; then
-    # Synapse fails to start while trying to parse IDP metadata if this package
-    # is not installed.
-    __package xmlsec1
+	# Synapse fails to start while trying to parse IDP metadata if this package
+	# is not installed.
+	__package xmlsec1
 
-    SAML2_IDP_METADATA_URL=$(cat "$__object/parameter/saml2-idp-metadata-url")
-    export SAML2_IDP_METADATA_URL
+	SAML2_IDP_METADATA_URL=$(cat "$__object/parameter/saml2-idp-metadata-url")
+	export SAML2_IDP_METADATA_URL
 fi
 
 if [ -f "$__object/parameter/saml2-sp-key" ]; then
-    SAML2_SP_KEY=$(cat "$__object/parameter/saml2-sp-key")
-    export SAML2_SP_KEY
+	SAML2_SP_KEY=$(cat "$__object/parameter/saml2-sp-key")
+	export SAML2_SP_KEY
 fi
 
 if [ -f "$__object/parameter/saml2-sp-cert" ]; then
-    SAML2_SP_CERT=$(cat "$__object/parameter/saml2-sp-cert")
-    export SAML2_SP_CERT
+	SAML2_SP_CERT=$(cat "$__object/parameter/saml2-sp-cert")
+	export SAML2_SP_CERT
 fi
 
 if [ -n "$SAML2_SP_KEY" ] && [ -z "$SAML2_SP_CERT" ]; then
-  echo "--saml2-sp-cert must be set if --saml2-sp-key is provided." >&2
-  exit 1
+	echo "--saml2-sp-cert must be set if --saml2-sp-key is provided." >&2
+	exit 1
 elif [ -n "$SAML2_SP_CERT" ] && [ -z "$SAML2_SP_KEY" ]; then
-  echo "--saml2-sp-key must be set if --saml2-sp-cert is provided." >&2
-  exit 1
+	echo "--saml2-sp-key must be set if --saml2-sp-cert is provided." >&2
+	exit 1
 fi
 
 if [ -f "$__object/parameter/default-identity-server" ]; then
-    DEFAULT_IDENTITY_SERVER=$(cat "$__object/parameter/default-identity-server")
-    export DEFAULT_IDENTITY_SERVER
+	DEFAULT_IDENTITY_SERVER=$(cat "$__object/parameter/default-identity-server")
+	export DEFAULT_IDENTITY_SERVER
 fi
 
+ENABLE_3PID_LOOKUPS='false'
+if [ -f "$__object/parameter/enable-3pid-lookup" ]; then
+	ENABLE_3PID_LOOKUPS='true'
+fi
+export ENABLE_3PID_LOOKUPS
+
 # Federation.
 ALLOW_PUBLIC_ROOMS_OVER_FEDERATION=$(get_boolean_for 'allow-public-room-over-federation')
 ALLOW_PUBLIC_ROOMS_WITHOUT_AUTH=$(get_boolean_for 'allow-public-rooms-without-auth')
@@ -321,16 +327,16 @@ export ENABLE_REPLICATION ENABLE_REDIS_SUPPORT WORKER_REPLICATION_SECRET \
 case "$DATABASE_ENGINE" in
 	sqlite3)
 		:
-	;;
+		;;
 	psycopg2)
 		when='database engine is psycopg2'
 		is_required_when "$DATABASE_HOST" '--database-host' "$when"
 		is_required_when "$DATABASE_USER" '--database-user' "$when"
-	;;
+		;;
 	*)
 		echo "Invalid database engine: $DATABASE_ENGINE." >&2
 		exit 1
-	;;
+		;;
 esac
 
 
@@ -348,13 +354,13 @@ mkdir -p "$__object/files"
 "$__type/files/log.config.sh" > "$__object/files/log.config"
 
 require="$synapse_req" __file "$synapse_conf_dir/homeserver.yaml" \
-  --owner $synapse_user \
-  --mode 600 \
-  --source "$__object/files/homeserver.yaml"
+	--owner $synapse_user \
+	--mode 600 \
+	--source "$__object/files/homeserver.yaml"
 require="$synapse_req" __file "$LOG_CONFIG_PATH" \
-  --owner $synapse_user \
-  --mode 600 \
-  --source "$__object/files/log.config"
+	--owner $synapse_user \
+	--mode 600 \
+	--source "$__object/files/log.config"
 
 for directory in $DATA_DIR $LOG_DIR; do
 	require="$synapse_req" __directory $directory \
diff --git a/type/__matrix_synapse/parameter/boolean b/type/__matrix_synapse/parameter/boolean
index 7ff48de..ac87271 100644
--- a/type/__matrix_synapse/parameter/boolean
+++ b/type/__matrix_synapse/parameter/boolean
@@ -17,3 +17,4 @@ user-directory-search-all-users
 enable-message-retention-policy
 worker-mode
 enable-url-preview
+enable-3pid-lookups