In the process of a Kilo to Liberty Upgrade and cannot live migrate VMs between Kilo and Liberty compute hosts. The Control nodes and a single Compute node have been upgraded to Liberty. We get the following error are in compute nodes log when we attempt to live migrate a instance from the Kilo node to Liberty;

Traceback (most recent call last):
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 5314, in live_migration
     block_migration, disk, dest, migrate_data)
   File "/usr/lib/python2.7/site-packages/nova/compute/rpcapi.py", line 623, in pre_live_migration
     disk=disk, migrate_data=migrate_data)
   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/client.py", line 156, in call
    retry=self.retry)
   File "/usr/lib/python2.7/site-packages/oslo_messaging/transport.py", line 90, in _send
    timeout=timeout, retry=retry)
   File "/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/amqpdriver.py", line 350, in send
     retry=retry)
   File "/usr/lib/python2.7/site-packages/oslo_messaging/_drivers/amqpdriver.py", line 341, in _send
     raise result
 RemoteError: Remote error: UnsupportedVersion Endpoint does not support RPC version 3.19. Attempted met
hod: pre_live_migration



Traceback (most recent call last):
   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 142, in _dispatch_and_reply
     executor_callback))
   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 186, in _dispatch
     executor_callback)
   File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 130, in _do_dispatch
     result = func(ctxt, **new_args)
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 6810, in live_migration
     migrate_data=migrate_data)
   File "/usr/lib/python2.7/site-packages/nova/exception.py", line 88, in wrapped
     payload)
   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 85, in __exit__
     six.reraise(self.type_, self.value, self.tb)
   File "/usr/lib/python2.7/site-packages/nova/exception.py", line 71, in wrapped
     return f(self, context, *args, **kw)
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 361, in decorated_function
     kwargs['instance'], e, sys.exc_info())
   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 85, in __exit__
     six.reraise(self.type_, self.value, self.tb)
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 349, in decorated_function
     return function(self, context, *args, **kwargs)
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 5322, in live_migration
     block_migration, migrate_data)
   File "/usr/lib/python2.7/site-packages/nova/exception.py", line 88, in wrapped
     payload)
   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 85, in __exit__
     six.reraise(self.type_, self.value, self.tb)
   File "/usr/lib/python2.7/site-packages/nova/exception.py", line 71, in wrapped
     return f(self, context, *args, **kw)
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 361, in decorated_function
     kwargs['instance'], e, sys.exc_info())
   File "/usr/lib/python2.7/site-packages/oslo_utils/excutils.py", line 85, in __exit__
     six.reraise(self.type_, self.value, self.tb)
   File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 349, in decorated_function
     return function(self, context, *args, **kwargs)
   File "/usr/lib/python2.7/site-packages/nova ...