diff --git a/.travis.yml b/.travis.yml
index 3ed2151..aab3b68 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ before_install:
   - export DJANGO_SETTINGS_MODULE=celery_haystack.test_settings
 install:
   - pip install -e .
-  - pip install -r requirements/v2.txt $DJANGO
+  - pip install -r requirements/v2.txt $DJANGO $CELERY
 before_script:
   - flake8 celery_haystack --ignore=E501,E731
 script:
@@ -19,6 +19,8 @@ env:
   - DJANGO="Django>=1.9,<1.10"
   - DJANGO="Django>=1.10,<1.11"
   - DJANGO="Django>=1.11,<1.12"
+  - CELERY="celery>=3.1,<4.0"
+  - CELERY="celery>=4.0,<5.0"
 
 notifications:
     irc: "irc.freenode.org#haystack"
diff --git a/README.rst b/README.rst
index 656fba1..c6edacb 100644
--- a/README.rst
+++ b/README.rst
@@ -14,7 +14,7 @@ Requirements
 
 * Django 1.8+
 * Haystack_ `2.X`_
-* Celery_ 3.X
+* Celery_ 3.X / 4.X
 
 You also need to install your choice of one of the supported search engines
 for Haystack and one of the supported backends for Celery.
diff --git a/celery_haystack/conf.py b/celery_haystack/conf.py
index 26f278a..b8d32e2 100644
--- a/celery_haystack/conf.py
+++ b/celery_haystack/conf.py
@@ -15,7 +15,9 @@ class CeleryHaystack(AppConf):
     #: The number of retries that are done
     MAX_RETRIES = 1
     #: The default Celery task class
-    DEFAULT_TASK = 'celery_haystack.tasks.CeleryHaystackSignalHandler'
+    DEFAULT_TASK = 'celery_haystack.tasks.haystack_signal_handler'
+    #: The update handler class
+    HANDLER = 'celery_haystack.handler.CeleryHaystackSignalHandler'
     #: The name of the celery queue to use, or None for default
     QUEUE = None
     #: Whether the task should be handled transaction safe
diff --git a/celery_haystack/exceptions.py b/celery_haystack/exceptions.py
new file mode 100644
index 0000000..af37c0e
--- /dev/null
+++ b/celery_haystack/exceptions.py
@@ -0,0 +1,35 @@
+import six
+
+
+class CeleryHaystackException(Exception):
+    pass
+
+
+@six.python_2_unicode_compatible
+class IndexOperationException(CeleryHaystackException):
+    def __init__(self, index, reason):
+        self.index = index
+        self.reason = reason
+
+    def __str__(self):
+        return "Failed to update index %s. %s" % (self.index, self.reason)
+
+
+@six.python_2_unicode_compatible
+class InstanceNotFoundException(CeleryHaystackException):
+    def __init__(self, model_class, pk, reason):
+        self.model_class = model_class
+        self.pk = pk
+        self.reason = reason
+
+    def __str__(self):
+        return "Unable to load instance %s with pk=%s. %s" % (self.model_class, self.pk, self.reason)
+
+
+@six.python_2_unicode_compatible
+class UnrecognizedActionException(CeleryHaystackException):
+    def __init__(self, action):
+        self.action = action
+
+    def __str__(self):
+        return "Unrecognized action '%s'" % self.action
diff --git a/celery_haystack/handler.py b/celery_haystack/handler.py
new file mode 100644
index 0000000..44cdc76
--- /dev/null
+++ b/celery_haystack/handler.py
@@ -0,0 +1,129 @@
+import logging
+from django.apps import apps
+from django.core.exceptions import ImproperlyConfigured
+from haystack import connection_router, connections
+from haystack.exceptions import NotHandled as IndexNotFoundException
+
+from celery_haystack import exceptions
+
+
+logger = logging.getLogger(__name__)
+
+
+class CeleryHaystackSignalHandler(object):
+    def __init__(self, identifier):
+        self.identifier = identifier
+
+        # First get the object path and pk (e.g. ('notes.note', 23))
+        self.object_path, self.pk = self.split_identifier(identifier)
+
+    @staticmethod
+    def split_identifier(identifier, **kwargs):
+        """
+        Break down the identifier representing the instance.
+
+        Converts 'notes.note.23' into ('notes.note', 23).
+        """
+        bits = identifier.split('.')
+
+        if len(bits) < 2:
+            raise ValueError("Unable to parse object identifer '%s'" % identifier)
+
+        pk = bits[-1]
+        # In case Django ever handles full paths...
+        object_path = '.'.join(bits[:-1])
+        return object_path, pk
+
+    def get_model_class(self):
+        """
+        Fetch the model's class in a standarized way.
+        """
+        bits = self.object_path.split('.')
+        app_name = '.'.join(bits[:-1])
+        classname = bits[-1]
+        model_class = apps.get_model(app_name, classname)
+
+        if model_class is None:
+            raise ImproperlyConfigured("Could not load model '%s'." %
+                                       self.object_path)
+        return model_class
+
+    @staticmethod
+    def get_instance(model_class, pk):
+        """
+        Fetch the instance in a standarized way.
+        """
+        try:
+            instance = model_class._default_manager.get(pk=pk)
+        except (model_class.DoesNotExist, model_class.MultipleObjectsReturned) as exc:
+            raise exceptions.InstanceNotFoundException(model_class, pk, reason=exc)
+
+        return instance
+
+    @staticmethod
+    def get_indexes(model_class):
+        """
+        Fetch the model's registered ``SearchIndex`` in a standarized way.
+        """
+        try:
+            using_backends = connection_router.for_write(**{'models': [model_class]})
+            for using in using_backends:
+                index_holder = connections[using].get_unified_index()
+                yield index_holder.get_index(model_class), using
+        except IndexNotFoundException:
+            raise ImproperlyConfigured("Couldn't find a SearchIndex for %s." % model_class)
+
+    @staticmethod
+    def get_index_name(index):
+        """
+            Get index name
+        """
+        return ".".join([index.__class__.__module__,
+                         index.__class__.__name__])
+
+    def handle_delete(self, current_index, using, model_class):
+        # If the object is gone, we'll use just the identifier
+        # against the index.
+        try:
+            current_index.remove_object(self.identifier, using=using)
+        except Exception as exc:
+            raise exceptions.IndexOperationException(index=current_index, reason=exc)
+        else:
+
+            msg = ("Deleted '%s' (with %s)" %
+                   (self.identifier, self.get_index_name(current_index)))
+            logger.debug(msg)
+
+    def handle_update(self, current_index, using, model_class):
+        # and the instance of the model class with the pk
+
+        instance = self.get_instance(model_class, self.pk)
+
+        # Call the appropriate handler of the current index and
+        # handle exception if neccessary
+        try:
+            current_index.update_object(instance, using=using)
+        except Exception as exc:
+            raise exceptions.IndexOperationException(index=current_index, reason=exc)
+        else:
+            msg = ("Updated '%s' (with %s)" %
+                   (self.identifier, self.get_index_name(current_index)))
+            logger.debug(msg)
+
+    def handle(self, action):
+        """
+        Trigger the actual index handler depending on the
+        given action ('update' or 'delete').
+        """
+
+        # Then get the model class for the object path
+        model_class = self.get_model_class()
+
+        for current_index, using in self.get_indexes(model_class):
+
+            if action == 'delete':
+                self.handle_delete(current_index, using, model_class)
+            elif action == 'update':
+                self.handle_update(current_index, using, model_class)
+            else:
+                raise exceptions.UnrecognizedActionException(action)
diff --git a/celery_haystack/tasks.py b/celery_haystack/tasks.py
index d8acedd..9a2629e 100644
--- a/celery_haystack/tasks.py
+++ b/celery_haystack/tasks.py
@@ -1,155 +1,48 @@
-from django.core.exceptions import ImproperlyConfigured
+from celery.app import shared_task
+from celery.utils.log import get_task_logger
 from django.core.management import call_command
-from django.apps import apps
 
+from .utils import get_handler
+from . import exceptions
 from .conf import settings
 
-from haystack import connections, connection_router
-from haystack.exceptions import NotHandled as IndexNotFoundException
-
-from celery.task import Task  # noqa
-from celery.utils.log import get_task_logger
-
 logger = get_task_logger(__name__)
 
 
-class CeleryHaystackSignalHandler(Task):
-    using = settings.CELERY_HAYSTACK_DEFAULT_ALIAS
-    max_retries = settings.CELERY_HAYSTACK_MAX_RETRIES
-    default_retry_delay = settings.CELERY_HAYSTACK_RETRY_DELAY
-
-    def split_identifier(self, identifier, **kwargs):
-        """
-        Break down the identifier representing the instance.
-
-        Converts 'notes.note.23' into ('notes.note', 23).
-        """
-        bits = identifier.split('.')
-
-        if len(bits) < 2:
-            logger.error("Unable to parse object "
-                         "identifer '%s'. Moving on..." % identifier)
-            return (None, None)
-
-        pk = bits[-1]
-        # In case Django ever handles full paths...
-        object_path = '.'.join(bits[:-1])
-        return (object_path, pk)
-
-    def get_model_class(self, object_path, **kwargs):
-        """
-        Fetch the model's class in a standarized way.
-        """
-        bits = object_path.split('.')
-        app_name = '.'.join(bits[:-1])
-        classname = bits[-1]
-        model_class = apps.get_model(app_name, classname)
-
-        if model_class is None:
-            raise ImproperlyConfigured("Could not load model '%s'." %
-                                       object_path)
-        return model_class
-
-    def get_instance(self, model_class, pk, **kwargs):
-        """
-        Fetch the instance in a standarized way.
-        """
-        instance = None
-        try:
-            instance = model_class._default_manager.get(pk=pk)
-        except model_class.DoesNotExist:
-            logger.error("Couldn't load %s.%s.%s. Somehow it went missing?" %
-                         (model_class._meta.app_label.lower(),
-                          model_class._meta.object_name.lower(), pk))
-        except model_class.MultipleObjectsReturned:
-            logger.error("More than one object with pk %s. Oops?" % pk)
-        return instance
-
-    def get_indexes(self, model_class, **kwargs):
-        """
-        Fetch the model's registered ``SearchIndex`` in a standarized way.
-        """
-        try:
-            using_backends = connection_router.for_write(**{'models': [model_class]})
-            for using in using_backends:
-                index_holder = connections[using].get_unified_index()
-                yield index_holder.get_index(model_class), using
-        except IndexNotFoundException:
-            raise ImproperlyConfigured("Couldn't find a SearchIndex for %s." %
-                                       model_class)
-
-    def run(self, action, identifier, **kwargs):
-        """
-        Trigger the actual index handler depending on the
-        given action ('update' or 'delete').
-        """
-        # First get the object path and pk (e.g. ('notes.note', 23))
-        object_path, pk = self.split_identifier(identifier, **kwargs)
-        if object_path is None or pk is None:
-            msg = "Couldn't handle object with identifier %s" % identifier
-            logger.error(msg)
-            raise ValueError(msg)
-
-        # Then get the model class for the object path
-        model_class = self.get_model_class(object_path, **kwargs)
-        for current_index, using in self.get_indexes(model_class, **kwargs):
-            current_index_name = ".".join([current_index.__class__.__module__,
-                                           current_index.__class__.__name__])
-
-            if action == 'delete':
-                # If the object is gone, we'll use just the identifier
-                # against the index.
-                try:
-                    current_index.remove_object(identifier, using=using)
-                except Exception as exc:
-                    logger.exception(exc)
-                    self.retry(exc=exc)
-                else:
-                    msg = ("Deleted '%s' (with %s)" %
-                           (identifier, current_index_name))
-                    logger.debug(msg)
-            elif action == 'update':
-                # and the instance of the model class with the pk
-                instance = self.get_instance(model_class, pk, **kwargs)
-                if instance is None:
-                    logger.debug("Failed updating '%s' (with %s)" %
-                                 (identifier, current_index_name))
-                    raise ValueError("Couldn't load object '%s'" % identifier)
-
-                # Call the appropriate handler of the current index and
-                # handle exception if neccessary
-                try:
-                    current_index.update_object(instance, using=using)
-                except Exception as exc:
-                    logger.exception(exc)
-                    self.retry(exc=exc)
-                else:
-                    msg = ("Updated '%s' (with %s)" %
-                           (identifier, current_index_name))
-                    logger.debug(msg)
-            else:
-                logger.error("Unrecognized action '%s'. Moving on..." % action)
-                raise ValueError("Unrecognized action %s" % action)
-
-
-class CeleryHaystackUpdateIndex(Task):
+@shared_task(bind=True,
+             using=settings.CELERY_HAYSTACK_DEFAULT_ALIAS,
+             max_retries=settings.CELERY_HAYSTACK_MAX_RETRIES,
+             default_retry_delay=settings.CELERY_HAYSTACK_RETRY_DELAY)
+def haystack_signal_handler(self, action, identifier, **kwargs):
+    try:
+        get_handler()(identifier).handle(action)
+    except exceptions.IndexOperationException as exc:
+        logger.exception(exc)
+        self.retry(exc=exc)
+    except exceptions.InstanceNotFoundException as exc:
+        logger.error(exc)
+    except exceptions.UnrecognizedActionException as exc:
+        logger.error("%s. Moving on..." % action)
+
+
+@shared_task()
+def celery_haystack_update_index(apps=None, **kwargs):
     """
     A celery task class to be used to call the update_index management
     command from Celery.
     """
-    def run(self, apps=None, **kwargs):
-        defaults = {
-            'batchsize': settings.CELERY_HAYSTACK_COMMAND_BATCH_SIZE,
-            'age': settings.CELERY_HAYSTACK_COMMAND_AGE,
-            'remove': settings.CELERY_HAYSTACK_COMMAND_REMOVE,
-            'using': [settings.CELERY_HAYSTACK_DEFAULT_ALIAS],
-            'workers': settings.CELERY_HAYSTACK_COMMAND_WORKERS,
-            'verbosity': settings.CELERY_HAYSTACK_COMMAND_VERBOSITY,
-        }
-        defaults.update(kwargs)
-        if apps is None:
-            apps = settings.CELERY_HAYSTACK_COMMAND_APPS
-        # Run the update_index management command
-        logger.info("Starting update index")
-        call_command('update_index', *apps, **defaults)
-        logger.info("Finishing update index")
+    defaults = {
+        'batchsize': settings.CELERY_HAYSTACK_COMMAND_BATCH_SIZE,
+        'age': settings.CELERY_HAYSTACK_COMMAND_AGE,
+        'remove': settings.CELERY_HAYSTACK_COMMAND_REMOVE,
+        'using': [settings.CELERY_HAYSTACK_DEFAULT_ALIAS],
+        'workers': settings.CELERY_HAYSTACK_COMMAND_WORKERS,
+        'verbosity': settings.CELERY_HAYSTACK_COMMAND_VERBOSITY,
+    }
+    defaults.update(kwargs)
+    if apps is None:
+        apps = settings.CELERY_HAYSTACK_COMMAND_APPS
+    # Run the update_index management command
+    logger.info("Starting update index")
+    call_command('update_index', *apps, **defaults)
+    logger.info("Finishing update index")
diff --git a/celery_haystack/utils.py b/celery_haystack/utils.py
index 9cb4938..8a05fb3 100644
--- a/celery_haystack/utils.py
+++ b/celery_haystack/utils.py
@@ -10,20 +10,24 @@
 from .conf import settings
 
 
-def get_update_task(task_path=None):
-    import_path = task_path or settings.CELERY_HAYSTACK_DEFAULT_TASK
-    module, attr = import_path.rsplit('.', 1)
+def get_class(import_path):
+    module_name, attr = import_path.rsplit('.', 1)
     try:
-        mod = import_module(module)
+        mod = import_module(module_name)
     except ImportError as e:
         raise ImproperlyConfigured('Error importing module %s: "%s"' %
-                                   (module, e))
+                                   (module_name, e))
     try:
-        Task = getattr(mod, attr)
+        update_task = getattr(mod, attr)
     except AttributeError:
         raise ImproperlyConfigured('Module "%s" does not define a "%s" '
-                                   'class.' % (module, attr))
-    return Task()
+                                   'class.' % (module_name, attr))
+    return update_task
+
+
+def get_update_task(task_path=None):
+    import_path = task_path or settings.CELERY_HAYSTACK_DEFAULT_TASK
+    return get_class(import_path)
 
 
 def enqueue_task(action, instance, **kwargs):
@@ -53,3 +57,7 @@ def enqueue_task(action, instance, **kwargs):
         )
     else:
         task_func()
+
+
+def get_handler():
+    return get_class(settings.CELERY_HAYSTACK_HANDLER)
diff --git a/requirements/v2.txt b/requirements/v2.txt
index 7e08873..18dca78 100644
--- a/requirements/v2.txt
+++ b/requirements/v2.txt
@@ -1,6 +1,4 @@
 django-discover-runner
-django-haystack
-celery
 Whoosh
 flake8
 coverage
diff --git a/setup.cfg b/setup.cfg
index ad6de1c..a482717 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -25,8 +25,11 @@ classifier =
     Programming Language :: Python :: 3.4
     Topic :: Utilities
 requires-dist =
+    django>=1.8,<1.12
     django-appconf>=0.4.1
-
+    six
+    celery>=3.1,<5.0
+    django-haystack>=2.0,<3.0
 
 [files]
 packages =