diff --git a/lower-constraints.txt b/lower-constraints.txt
index 0f4b8f547..cdb78db26 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -81,7 +81,7 @@ oslo.context==2.19.2
 oslo.db==4.27.0
 oslo.i18n==3.15.3
 oslo.log==3.36.0
-oslo.messaging==5.29.0
+oslo.messaging==6.3.0
 oslo.middleware==3.31.0
 oslo.policy==1.35.0
 oslo.privsep==1.23.0
diff --git a/nova/conf/__init__.py b/nova/conf/__init__.py
index 377435add..7649e3d66 100644
--- a/nova/conf/__init__.py
+++ b/nova/conf/__init__.py
@@ -55,6 +55,7 @@ from nova.conf import powervm
 from nova.conf import quota
 from nova.conf import rdp
 from nova.conf import remote_debug
+from nova.conf import rpc
 from nova.conf import scheduler
 from nova.conf import serial_console
 from nova.conf import service
@@ -107,6 +108,7 @@ placement.register_opts(CONF)
 powervm.register_opts(CONF)
 quota.register_opts(CONF)
 rdp.register_opts(CONF)
+rpc.register_opts(CONF)
 scheduler.register_opts(CONF)
 serial_console.register_opts(CONF)
 service.register_opts(CONF)
diff --git a/nova/tests/fixtures.py b/nova/tests/fixtures.py
index 876679c0c..23d2f026c 100644
--- a/nova/tests/fixtures.py
+++ b/nova/tests/fixtures.py
@@ -484,13 +484,15 @@ class CellDatabases(fixtures.Fixture):
                                         executor='eventlet',
                                         serializer=serializer)
 
-    def _wrap_get_client(self, target, version_cap=None, serializer=None):
+    def _wrap_get_client(self, target, version_cap=None, serializer=None,
+                         call_monitor_timeout=None):
         """Mirror rpc.get_client() but with our special sauce."""
         serializer = CheatingSerializer(serializer)
         return messaging.RPCClient(rpc.TRANSPORT,
                                    target,
                                    version_cap=version_cap,
-                                   serializer=serializer)
+                                   serializer=serializer,
+                                   call_monitor_timeout=call_monitor_timeout)
 
     def add_cell_database(self, connection_str, default=False):
         """Add a cell database to the fixture.
diff --git a/requirements.txt b/requirements.txt
index ac59f6fb4..7e090f31d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -43,7 +43,7 @@ oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
 oslo.utils>=3.33.0 # Apache-2.0
 oslo.db>=4.27.0 # Apache-2.0
 oslo.rootwrap>=5.8.0 # Apache-2.0
-oslo.messaging>=5.29.0 # Apache-2.0
+oslo.messaging>=6.3.0 # Apache-2.0
 oslo.policy>=1.35.0 # Apache-2.0
 oslo.privsep>=1.23.0 # Apache-2.0
 oslo.i18n>=3.15.3 # Apache-2.0