diff --git a/swh/scheduler/celery_backend/listener.py b/swh/scheduler/celery_backend/listener.py
--- a/swh/scheduler/celery_backend/listener.py
+++ b/swh/scheduler/celery_backend/listener.py
@@ -5,6 +5,7 @@
 
 import click
 import datetime
+import logging
 import socket
 
 from arrow import utcnow
@@ -26,22 +27,29 @@
                            exchange=self.exchange,
                            routing_key=self.routing_key,
                            auto_delete=False,
-                           durable=True,
-                           queue_arguments=self._get_queue_arguments())
+                           durable=True)
 
     def get_consumers(self, consumer, channel):
         return [consumer(queues=[self.queue],
                          callbacks=[self._receive], no_ack=False,
                          accept=self.accept)]
 
-    def _receive(self, body, message):
-        type, body = self.event_from_message(body)
-        self.process(type, body, message)
+    def _receive(self, bodies, message):
+        logging.debug('## event-receiver: bodies: %s' % bodies)
+        logging.debug('## event-receiver: message: %s' % message)
+        if not isinstance(bodies, list):  # celery<4 returned body as element
+            bodies = [bodies]
+        for body in bodies:
+            type, body = self.event_from_message(body)
+            self.process(type, body, message)
 
     def process(self, type, event, message):
         """Process the received event by dispatching it to the appropriate
         handler."""
         handler = self.handlers.get(type) or self.handlers.get('*')
+        logging.debug('## event-receiver: type: %s' % type)
+        logging.debug('## event-receiver: event: %s' % event)
+        logging.debug('## event-receiver: handler: %s' % handler)
         handler and handler(event, message)
 
 
@@ -93,6 +101,9 @@
         try_perform_actions()
 
     def task_started(event, message):
+        logging.debug('#### task_started: event: %s' % event)
+        logging.debug('#### task_started: message: %s' % message)
+
         queue_action({
             'action': 'start_task_run',
             'args': [event['uuid']],
@@ -106,8 +117,11 @@
         })
 
     def task_succeeded(event, message):
+        logging.debug('#### task_succeeded: event: %s' % event)
+        logging.debug('#### task_succeeded: message: %s' % message)
         result = event['result']
 
+        logging.debug('#### task_succeeded: result: %s' % result)
         try:
             status = result.get('status')
             if status == 'success':
@@ -127,6 +141,9 @@
         })
 
     def task_failed(event, message):
+        logging.debug('#### task_failed: event: %s' % event)
+        logging.debug('#### task_failed: message: %s' % message)
+
         queue_action({
             'action': 'end_task_run',
             'args': [event['uuid']],
@@ -159,7 +176,12 @@
     '--database', '-d', help='Scheduling database DSN')
 @click.option('--url', '-u',
               help="(Optional) Scheduler's url access")
-def main(cls, database, url):
+@click.option('--verbose', is_flag=True, default=False,
+              help='Default to be silent')
+def main(cls, database, url, verbose):
+    if verbose:
+        logging.basicConfig(level=logging.DEBUG if verbose else logging.INFO)
+
     scheduler = None
     override_config = {}
     if cls == 'local':