diff --git a/README.md b/README.md
index dc02bae6..1e067a6a 100644
--- a/README.md
+++ b/README.md
@@ -2,11 +2,11 @@
     =====================================
     generator=datazen
     version=3.1.2
-    hash=cde638b7567222966c038f6c0d5719e0
+    hash=3bc7656b5df806d21148ec2b5b2c0082
     =====================================
 -->
 
-# runtimepy ([1.5.3](https://pypi.org/project/runtimepy/))
+# runtimepy ([1.5.4](https://pypi.org/project/runtimepy/))
 
 [![python](https://img.shields.io/pypi/pyversions/runtimepy.svg)](https://pypi.org/project/runtimepy/)
 ![Build Status](https://github.com/vkottler/runtimepy/workflows/Python%20Package/badge.svg)
diff --git a/local/variables/package.yaml b/local/variables/package.yaml
index fba43cfe..edaad82c 100644
--- a/local/variables/package.yaml
+++ b/local/variables/package.yaml
@@ -1,5 +1,5 @@
 ---
 major: 1
 minor: 5
-patch: 3
+patch: 4
 entry: runtimepy
diff --git a/pyproject.toml b/pyproject.toml
index 73d905e1..0dc21004 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta:__legacy__"
 
 [project]
 name = "runtimepy"
-version = "1.5.3"
+version = "1.5.4"
 description = "A framework for implementing Python services."
 readme = "README.md"
 requires-python = ">=3.7"
diff --git a/runtimepy/__init__.py b/runtimepy/__init__.py
index 04600dcb..2d6b5be3 100644
--- a/runtimepy/__init__.py
+++ b/runtimepy/__init__.py
@@ -1,7 +1,7 @@
 # =====================================
 # generator=datazen
 # version=3.1.2
-# hash=407407f958d18e14776eb5ad2afb0772
+# hash=d02bf554f7d30131decd07af8dbad01f
 # =====================================
 
 """
@@ -10,4 +10,4 @@
 
 DESCRIPTION = "A framework for implementing Python services."
 PKG_NAME = "runtimepy"
-VERSION = "1.5.3"
+VERSION = "1.5.4"
diff --git a/runtimepy/net/udp/connection.py b/runtimepy/net/udp/connection.py
index 8473073b..a4524b98 100644
--- a/runtimepy/net/udp/connection.py
+++ b/runtimepy/net/udp/connection.py
@@ -99,15 +99,24 @@ def sendto(
         self, data: bytes, addr: _Union[IpHost, _Tuple[str, int]] = None
     ) -> None:
         """Send to a specific address."""
-        self._transport.sendto(data, addr=addr)
+
+        try:
+            self._transport.sendto(data, addr=addr)
+
+        # Catch a bug in the underlying event loop implementation - we try to
+        # send, but the underlying socket is gone (e.g. attribute is 'None').
+        # This seems to be possible (but intermittent) when shutting down the
+        # application.
+        except AttributeError as exc:
+            self.disable(str(exc))
 
     def send_text(self, data: str) -> None:
         """Enqueue a text message to send."""
-        self._transport.sendto(data.encode(), addr=self.remote_address)
+        self.sendto(data.encode(), addr=self.remote_address)
 
     def send_binary(self, data: _BinaryMessage) -> None:
         """Enqueue a binary message tos end."""
-        self._transport.sendto(data, addr=self.remote_address)
+        self.sendto(data, addr=self.remote_address)
 
     @classmethod
     async def create_connection(
diff --git a/tests/net/udp/test_sendto_exceptions.py b/tests/net/udp/test_sendto_exceptions.py
new file mode 100644
index 00000000..2934dded
--- /dev/null
+++ b/tests/net/udp/test_sendto_exceptions.py
@@ -0,0 +1,65 @@
+"""
+Test special cases for the 'net.udp.connection' module.
+"""
+
+# built-in
+from asyncio import Event, gather, sleep
+
+# third-party
+from pytest import mark
+
+# module under test
+from runtimepy.net.udp.connection import NullUdpConnection
+
+
+@mark.asyncio
+async def test_udp_connection_sendto_fail():
+    """Test 'sendto' failures with a UDP connection."""
+
+    conn1, conn2 = await NullUdpConnection.create_pair()
+
+    iterations = 0
+    sleep_time = 0.05
+
+    signal = Event()
+
+    async def send_spam() -> None:
+        """Send messages back and forth."""
+
+        nonlocal iterations
+        msg = "Hello, world!"
+
+        while not conn1.disabled and not conn2.disabled:
+            conn1.send_text(msg)
+            conn2.send_text(msg)
+            iterations += 1
+            await sleep(sleep_time)
+
+        for _ in range(10):
+            conn1.send_text(msg)
+            conn2.send_text(msg)
+            iterations += 1
+            await sleep(sleep_time)
+
+        await signal.wait()
+
+        # Send more (should cause problems).
+        for _ in range(10):
+            conn1.send_text(msg)
+            conn2.send_text(msg)
+
+    async def closer() -> None:
+        """Close the two connections."""
+
+        while iterations < 5:
+            await sleep(sleep_time)
+            conn1.disable("nominal")
+
+        while iterations < 10:
+            await sleep(sleep_time)
+            conn2.disable("nominal")
+
+        signal.set()
+
+    # Run everything.
+    await gather(send_spam(), closer(), conn1.process(), conn2.process())