Python stomp client can not receive any message from Spring 2.x Stomp Service - spring

Question

My spring 1.5 based stomp websocket server and python based stomp client was working fine.
After upgrading spring version to 2.x, the client no longer receives any messages. I have consulted the spring guide but can't find anything wrong.
Python based stomp client:
import stomper
from websocket import create_connection
ws = create_connection('ws://localhost:8080/ws')
ws.send(stomper.subscribe('/msg', 0))
print(ws.recv())
Spring 1.5 based stomp server:
#Configuration
#EnableWebSocketMessageBroker
class DemoConfig extends AbstractWebSocketMessageBrokerConfigurer {
#Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/msg");
registry.setApplicationDestinationPrefixes("/app");
}
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("ws");
}
}
#Component
#EnableScheduling
class MessageBroker {
#Autowired
private SimpMessagingTemplate messenger;
#Scheduled(fixedRate = 1000)
private void msg() {
messenger.convertAndSend("/msg", "hello");
}
}
Spring 2.x based stomp server(Implement an interface without extending the abstract class):
#Configuration
#EnableWebSocketMessageBroker
class DemoConfig implements WebSocketMessageBrokerConfigurer {
#Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/msg");
registry.setApplicationDestinationPrefixes("/app");
}
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("ws");
}
}
#Component
#EnableScheduling
class MessageBroker {
#Autowired
private SimpMessagingTemplate messenger;
#Scheduled(fixedRate = 1000)
private void msg() {
messenger.convertAndSend("/msg", "hello");
}
}