diff --git a/kobo/hub/migrations/0004_alter_task_worker.py b/kobo/hub/migrations/0004_alter_task_worker.py
new file mode 100644
index 00000000..3ed6314f
--- /dev/null
+++ b/kobo/hub/migrations/0004_alter_task_worker.py
@@ -0,0 +1,19 @@
+# Generated by Django 4.0.10 on 2023-08-30 08:41
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('hub', '0003_auto_20160202_0647'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='task',
+            name='worker',
+            field=models.ForeignKey(blank=True, help_text='A worker which has this task assigned.', null=True, on_delete=django.db.models.deletion.SET_NULL, to='hub.worker'),
+        ),
+    ]
diff --git a/kobo/hub/models.py b/kobo/hub/models.py
index 456b602c..d3f3168c 100644
--- a/kobo/hub/models.py
+++ b/kobo/hub/models.py
@@ -549,7 +549,7 @@ class Task(models.Model):
     """Model for hub_task table."""
     archive             = models.BooleanField(default=False, help_text=_("When a task is archived, it disappears from admin interface and cannot be accessed by taskd.<br />Make sure that archived tasks are finished and you won't need them anymore."))
     owner               = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
-    worker              = models.ForeignKey(Worker, null=True, blank=True, help_text=_("A worker which has this task assigned."), on_delete=models.CASCADE)
+    worker              = models.ForeignKey(Worker, null=True, blank=True, help_text=_("A worker which has this task assigned."), on_delete=models.SET_NULL)
     parent              = models.ForeignKey("self", null=True, blank=True, help_text=_("Parent task."), on_delete=models.CASCADE)
     state               = models.PositiveIntegerField(default=TASK_STATES["FREE"], choices=TASK_STATES.get_mapping(), help_text=_("Current task state."))
     label               = models.CharField(max_length=255, blank=True, help_text=_("Label, description or any reason for this task."))