diff --git a/netbox/extras/models/customfields.py b/netbox/extras/models/customfields.py
index cc96a25c1..1d84a3f4f 100644
--- a/netbox/extras/models/customfields.py
+++ b/netbox/extras/models/customfields.py
@@ -21,6 +21,7 @@ from netbox.models import ChangeLoggedModel
 from netbox.models.features import CloningMixin, ExportTemplatesMixin
 from netbox.search import FieldTypes
 from utilities import filters
+from utilities.datetime import datetime_from_timestamp
 from utilities.forms.fields import (
     CSVChoiceField, CSVModelChoiceField, CSVModelMultipleChoiceField, CSVMultipleChoiceField, DynamicChoiceField,
     DynamicModelChoiceField, DynamicModelMultipleChoiceField, DynamicMultipleChoiceField, JSONField, LaxURLField,
@@ -672,12 +673,8 @@ class CustomField(CloningMixin, ExportTemplatesMixin, ChangeLoggedModel):
             # Validate date & time
             elif self.type == CustomFieldTypeChoices.TYPE_DATETIME:
                 if type(value) is not datetime:
-                    # Work around UTC issue for Python < 3.11; see
-                    # https://docs.python.org/3/library/datetime.html#datetime.datetime.fromisoformat
-                    if type(value) is str and value.endswith('Z'):
-                        value = f'{value[:-1]}+00:00'
                     try:
-                        datetime.fromisoformat(value)
+                        datetime_from_timestamp(value)
                     except ValueError:
                         raise ValidationError(
                             _("Date and time values must be in ISO 8601 format (YYYY-MM-DD HH:MM:SS).")
diff --git a/netbox/utilities/datetime.py b/netbox/utilities/datetime.py
index 2ec35af98..d54ea7c46 100644
--- a/netbox/utilities/datetime.py
+++ b/netbox/utilities/datetime.py
@@ -1,7 +1,10 @@
+import datetime
+
 from django.utils import timezone
 from django.utils.timezone import localtime
 
 __all__ = (
+    'datetime_from_timestamp',
     'local_now',
 )
 
@@ -11,3 +14,15 @@ def local_now():
     Return the current date & time in the system timezone.
     """
     return localtime(timezone.now())
+
+
+def datetime_from_timestamp(value):
+    """
+    Convert an ISO 8601 or RFC 3339 timestamp to a datetime object.
+    """
+    # Work around UTC issue for Python < 3.11; see
+    # https://docs.python.org/3/library/datetime.html#datetime.datetime.fromisoformat
+    # TODO: Remove this once Python 3.10 is no longer supported
+    if type(value) is str and value.endswith('Z'):
+        value = f'{value[:-1]}+00:00'
+    return datetime.datetime.fromisoformat(value)
diff --git a/netbox/utilities/release.py b/netbox/utilities/release.py
index dacec1010..e41e6d2bf 100644
--- a/netbox/utilities/release.py
+++ b/netbox/utilities/release.py
@@ -6,6 +6,8 @@ from typing import Union
 
 from django.core.exceptions import ImproperlyConfigured
 
+from utilities.datetime import datetime_from_timestamp
+
 RELEASE_PATH = 'release.yaml'
 LOCAL_RELEASE_PATH = 'local/release.yaml'
 
@@ -52,6 +54,6 @@ def load_release_data():
 
     # Convert the published date to a date object
     if 'published' in data:
-        data['published'] = datetime.date.fromisoformat(data['published'])
+        data['published'] = datetime_from_timestamp(data['published'])
 
     return ReleaseInfo(**data)