diff --git a/pycyphal/_version.py b/pycyphal/_version.py
index 6cea18d8..4a7bff54 100644
--- a/pycyphal/_version.py
+++ b/pycyphal/_version.py
@@ -1 +1 @@
-__version__ = "1.18.0"
+__version__ = "1.18.1"
diff --git a/pycyphal/transport/udp/_udp.py b/pycyphal/transport/udp/_udp.py
index 20965946..85d1991a 100644
--- a/pycyphal/transport/udp/_udp.py
+++ b/pycyphal/transport/udp/_udp.py
@@ -64,7 +64,7 @@ class UDPTransport(pycyphal.transport.Transport):
     def __init__(
         self,
         local_ip_address: IPAddress | str,
-        local_node_id: typing.Optional[int] = 0,
+        local_node_id: typing.Optional[int],
         *,  # The following parameters are keyword-only.
         mtu: int = MTU_DEFAULT,
         service_transfer_multiplier: int = 1,