diff --git a/aleksis/core/models.py b/aleksis/core/models.py
index 4c9c28ea657b98dea8c14188bac0e19cad048ab2..35878269058c159e6609c222c16509773b940466 100644
--- a/aleksis/core/models.py
+++ b/aleksis/core/models.py
@@ -21,6 +21,7 @@ from django.utils.translation import gettext_lazy as _
 import jsonstore
 from cache_memoize import cache_memoize
 from dynamic_preferences.models import PerInstancePreferenceModel
+from model_utils.models import TimeStampedModel
 from phonenumber_field.modelfields import PhoneNumberField
 from polymorphic.models import PolymorphicModel
 
@@ -440,7 +441,7 @@ class PersonGroupThrough(ExtensibleModel):
             setattr(self, field_name, field_instance)
 
 
-class Activity(ExtensibleModel):
+class Activity(ExtensibleModel, TimeStampedModel):
     """Activity of a user to trace some actions done in AlekSIS in displayable form."""
 
     user = models.ForeignKey(
@@ -460,7 +461,7 @@ class Activity(ExtensibleModel):
         verbose_name_plural = _("Activities")
 
 
-class Notification(ExtensibleModel):
+class Notification(ExtensibleModel, TimeStampedModel):
     """Notification to submit to a user."""
 
     sender = models.CharField(max_length=100, verbose_name=_("Sender"))
diff --git a/aleksis/core/templates/core/index.html b/aleksis/core/templates/core/index.html
index 683adca900d46a8ba50790829db4d3ecd0ba2716..bcf0bf1b4180756d53f1519b8ee2371ee3e4e658 100644
--- a/aleksis/core/templates/core/index.html
+++ b/aleksis/core/templates/core/index.html
@@ -48,7 +48,7 @@
                 <span class="badge new primary-color">{{ activity.app }}</span>
                 <span class="title">{{ activity.title }}</span>
                 <p>
-                  <i class="material-icons left">access_time</i> {{ activity.created_at }}
+                  <i class="material-icons left">access_time</i> {{ activity.created }}
                 </p>
                 <p>
                   {{ activity.description }}
@@ -71,7 +71,7 @@
                 <span class="badge new primary-color">{{ notification.app }}</span>
                 <span class="title">{{ notification.title }}</span>
                 <p>
-                  <i class="material-icons left">access_time</i> {{ notification.created_at }}
+                  <i class="material-icons left">access_time</i> {{ notification.created }}
                 </p>
                 <p>
                   {{ notification.description }}
diff --git a/aleksis/core/templates/templated_email/notification.email b/aleksis/core/templates/templated_email/notification.email
index 8e61fd0df28b5bc6342c891921831e147e9cc8d9..0e5d9bdee3c8bd9ec3df5c9d008ae68d1f274c23 100644
--- a/aleksis/core/templates/templated_email/notification.email
+++ b/aleksis/core/templates/templated_email/notification.email
@@ -15,7 +15,7 @@
         {% trans "More information" %} → {{ notification.link }}
     {% endif %}
 
-    {% blocktrans with trans_sender=notification.sender trans_created_at=notification.created_at %}
+    {% blocktrans with trans_sender=notification.sender trans_created_at=notification.created %}
         Sent by {{ trans_sender }} at {{ trans_created_at }}
     {% endblocktrans %}
 
@@ -37,7 +37,7 @@
     </blockquote>
 
     <p>
-        {% blocktrans with trans_sender=notification.sender trans_created_at=notification.created_at %}
+        {% blocktrans with trans_sender=notification.sender trans_created_at=notification.created %}
             Sent by {{ trans_sender }} at {{ trans_created_at }}
         {% endblocktrans %}
     </p>