diff --git a/src/shared/varlink-io.systemd.Network.c b/src/shared/varlink-io.systemd.Network.c
index e2da5810e3..7477d42de8 100644
--- a/src/shared/varlink-io.systemd.Network.c
+++ b/src/shared/varlink-io.systemd.Network.c
@@ -7,7 +7,7 @@ static VARLINK_DEFINE_METHOD(GetStates,
                              VARLINK_DEFINE_OUTPUT(IPv4AddressState, VARLINK_STRING, 0),
                              VARLINK_DEFINE_OUTPUT(IPv6AddressState, VARLINK_STRING, 0),
                              VARLINK_DEFINE_OUTPUT(CarrierState, VARLINK_STRING, 0),
-                             VARLINK_DEFINE_OUTPUT(OnlineState, VARLINK_STRING, 0),
+                             VARLINK_DEFINE_OUTPUT(OnlineState, VARLINK_STRING, VARLINK_NULLABLE),
                              VARLINK_DEFINE_OUTPUT(OperationalState, VARLINK_STRING, 0));
 
 static VARLINK_DEFINE_METHOD(GetNamespaceId,