diff --git a/task/models.py b/task/models.py
index e305c4f..d3ce361 100644
--- a/task/models.py
+++ b/task/models.py
@@ -221,6 +221,22 @@ class Meta:
     def __str__(self) -> str:
         return '{}: {}'.format(self.task, self.rule)
 
+    @transaction.atomic
+    def clean_scheduled(self) -> List[int]:
+        """
+        Clean all scheduled chunks which are no longer valid.
+        Returns the ids of all chunks that were deleted.
+        """
+        chunks = self.chunks.filter(day__lt=self.start)
+        if self.end:
+            chunks |= self.chunks.filter(day__gt=self.end)
+        ids = [chunk.id for chunk in chunks]
+        chunks.delete()
+
+        self.last_scheduled_day = self.chunks.aggregate(Max('day'))['day__max']
+        self.save(update_fields=('last_scheduled_day',))
+        return ids
+
     @transaction.atomic
     def schedule(
             self,
diff --git a/task/tests.py b/task/tests.py
index e546360..ac8dd5f 100644
--- a/task/tests.py
+++ b/task/tests.py
@@ -3859,6 +3859,100 @@ def test_create_scheduled_task_duration(self):
                 Decimal(scheduled['task']['scheduled_duration']),
                 self.task.scheduled_duration)
 
+    @freeze_time('2010-05-03')
+    def test_update_cleaning(self):
+        """
+        Test the cleaning of task chunks when modifying the end date.
+        """
+        series = TaskChunkSeries.objects.create(
+            task=self.task,
+            start=date(2010, 5, 3),
+            end=date(2010, 5, 24),
+            rule='interval',
+            interval_days=7)
+        series.schedule()
+
+        self.assertEqual(
+            TaskChunkSeries.objects.count(),
+            1)
+        self.assertEqual(
+            TaskChunk.objects.count(),
+            4)
+
+        resp = self.client.put('/task/chunk/series/{}/'.format(series.pk), {
+            'task_id': self.task.pk,
+            'duration': '2',
+            'start': '2010-05-03',
+            'end': '2010-05-10',
+            'rule': 'interval',
+            'interval_days': 7,
+        })
+        self.assertEqual(
+            resp.status_code,
+            status.HTTP_200_OK)
+
+        self.assertSetEqual(
+            set(resp.data.keys()),
+            {'series', 'cleaned', 'scheduled'})
+
+        self.assertEqual(
+            len(resp.data['cleaned']),
+            2)
+        self.assertEqual(
+            len(resp.data['scheduled']),
+            0)
+
+        self.assertEqual(
+            TaskChunk.objects.count(),
+            2)
+
+    @freeze_time('2010-05-03')
+    def test_update_scheduling(self):
+        """
+        Test the scheduling of task chunks when modifying the end date.
+        """
+        series = TaskChunkSeries.objects.create(
+            task=self.task,
+            start=date(2010, 5, 3),
+            end=date(2010, 5, 24),
+            rule='interval',
+            interval_days=7)
+        series.schedule()
+
+        self.assertEqual(
+            TaskChunkSeries.objects.count(),
+            1)
+        self.assertEqual(
+            TaskChunk.objects.count(),
+            4)
+
+        resp = self.client.put('/task/chunk/series/{}/'.format(series.pk), {
+            'task_id': self.task.pk,
+            'duration': '2',
+            'start': '2010-05-03',
+            'end': '2010-06-7',
+            'rule': 'interval',
+            'interval_days': 7,
+        })
+        self.assertEqual(
+            resp.status_code,
+            status.HTTP_200_OK)
+
+        self.assertSetEqual(
+            set(resp.data.keys()),
+            {'series', 'cleaned', 'scheduled'})
+
+        self.assertEqual(
+            len(resp.data['cleaned']),
+            0)
+        self.assertEqual(
+            len(resp.data['scheduled']),
+            2)
+
+        self.assertEqual(
+            TaskChunk.objects.count(),
+            6)
+
     def test_partial_update(self):
         """
         Test that it is not allowed to partially update a task chunk series.
diff --git a/task/views.py b/task/views.py
index ce1c475..8c80d2e 100644
--- a/task/views.py
+++ b/task/views.py
@@ -2,7 +2,7 @@
 from django.db.models import F
 from rest_framework import mixins, serializers, status, viewsets
 from rest_framework.decorators import action
-from rest_framework.exceptions import MethodNotAllowed, ParseError, ValidationError
+from rest_framework.exceptions import ParseError, ValidationError
 from rest_framework.generics import get_object_or_404
 from rest_framework.permissions import IsAuthenticated
 from rest_framework.response import Response
@@ -38,7 +38,7 @@ def merge(self, request, pk: int, other_pk: int):
 
 
 class TaskChunkSeriesViewSet(viewsets.GenericViewSet, mixins.ListModelMixin,
-                             mixins.RetrieveModelMixin, mixins.UpdateModelMixin):
+                             mixins.RetrieveModelMixin):
     permission_classes = IsAuthenticated,
     serializer_class = TaskChunkSeriesSerializer
 
@@ -60,8 +60,23 @@ def create(self, request, *args, **kwargs):
             'scheduled': scheduled_serializer.data,
         }, status=status.HTTP_201_CREATED)
 
-    def partial_update(self, request, *args, **kwargs):
-        raise MethodNotAllowed('PATCH')
+    @transaction.atomic
+    def update(self, request, *args, **kwargs):
+        instance = self.get_object()
+        serializer = self.get_serializer(instance, data=request.data)
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+
+        cleaned = instance.clean_scheduled()
+
+        scheduled = instance.schedule()
+        scheduled_serializer = TaskChunkSerializer(scheduled, many=True)
+
+        return Response({
+            'series': serializer.data,
+            'scheduled': scheduled_serializer.data,
+            'cleaned': cleaned,
+        })
 
 
 class TaskChunkViewSet(viewsets.GenericViewSet, mixins.CreateModelMixin,