diff --git a/invenio_requests/records/systemfields/expired_state.py b/invenio_requests/records/systemfields/expired_state.py
index e3be42b6..06be37e4 100644
--- a/invenio_requests/records/systemfields/expired_state.py
+++ b/invenio_requests/records/systemfields/expired_state.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 #
 # Copyright (C) 2021 - 2022 TU Wien.
+# Copyright (C) 2025 Graz University of Technology.
 #
 # Invenio-Requests is free software; you can redistribute it and/or modify
 # it under the terms of the MIT License; see LICENSE file for more details.
@@ -8,9 +9,9 @@
 """Systemfield for calculating the ``is_expired`` property of a request."""
 
 
-from datetime import datetime
+from datetime import datetime, timezone
 
-import pytz
+import arrow
 from invenio_records_resources.records.systemfields.calculated import CalculatedField
 
 
@@ -29,10 +30,7 @@ def calculate(self, record):
         if expires_at is None:
             return False
 
-        # comparing timezone-aware and naive datetimes results in an error
-        # https://docs.python.org/3/library/datetime.html#determining-if-an-object-is-aware-or-naive # noqa
-        now = datetime.utcnow()
-        if expires_at.tzinfo and expires_at.tzinfo.utcoffset(expires_at) is not None:
-            now = now.replace(tzinfo=pytz.utc)
+        expires_at = arrow.get(expires_at, tzinfo=timezone.utc).datetime
+        now = datetime.now(timezone.utc)
 
         return expires_at < now
diff --git a/invenio_requests/services/schemas.py b/invenio_requests/services/schemas.py
index 5fce46a9..10fec382 100644
--- a/invenio_requests/services/schemas.py
+++ b/invenio_requests/services/schemas.py
@@ -18,6 +18,7 @@
     fields,
 )
 from marshmallow_utils import fields as utils_fields
+from marshmallow_utils.context import context_schema
 
 from invenio_requests.proxies import current_requests
 
@@ -43,14 +44,15 @@ class RequestEventSchema(BaseRecordSchema):
     def get_permissions(self, obj):
         """Return permissions to act on comments or empty dict."""
         is_comment = obj.type == CommentEventType
+        current_identity = context_schema.get()["identity"]
         if is_comment:
             service = current_requests.request_events_service
             return {
                 "can_update_comment": service.check_permission(
-                    self.context["identity"], "update_comment", event=obj
+                    current_identity, "update_comment", event=obj
                 ),
                 "can_delete_comment": service.check_permission(
-                    self.context["identity"], "delete_comment", event=obj
+                    current_identity, "delete_comment", event=obj
                 ),
             }
         else:
diff --git a/invenio_requests/tasks.py b/invenio_requests/tasks.py
index 2667bdf5..29ef1279 100644
--- a/invenio_requests/tasks.py
+++ b/invenio_requests/tasks.py
@@ -1,14 +1,14 @@
 # -*- coding: utf-8 -*-
 #
 # This file is part of Invenio.
-# Copyright (C) 2022 Graz University of Technology.
+# Copyright (C) 2022-2025 Graz University of Technology.
 #
 # Invenio is free software; you can redistribute it and/or modify it
 # under the terms of the MIT License; see LICENSE file for more details.
 
 """Celery tasks for requests."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 
 from celery import shared_task
 from flask import current_app
@@ -25,7 +25,7 @@
 def check_expired_requests():
     """Retrieve expired requests and perform expired action."""
     service = current_requests_service
-    now = datetime.utcnow().isoformat()
+    now = datetime.now(timezone.utc).isoformat()
 
     # using scan to get all requests
     requests_list = service.scan(
diff --git a/tests/records/systemfields/test_calculated_systemfield.py b/tests/records/systemfields/test_calculated_systemfield.py
index 0c58baca..2bc5fcec 100644
--- a/tests/records/systemfields/test_calculated_systemfield.py
+++ b/tests/records/systemfields/test_calculated_systemfield.py
@@ -1,13 +1,14 @@
 # -*- coding: utf-8 -*-
 #
 # Copyright (C) 2021 TU Wien.
+# Copyright (C) 2025 Graz University of Technology.
 #
 # Invenio-Requests is free software; you can redistribute it and/or modify it
 # under the terms of the MIT License; see LICENSE file for more details.
 
 """Test the calculated systemfields."""
 
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 
 import pytest
 
@@ -16,7 +17,7 @@
 
 def test_expired_systemfield(example_request):
     """Test if the expired system field works as intended."""
-    now = datetime.utcnow()
+    now = datetime.now(timezone.utc)
     example_request.expires_at = None
     example_request.commit()
 
diff --git a/tests/services/requests/test_requests_tasks.py b/tests/services/requests/test_requests_tasks.py
index cd4f24ec..b485c2c5 100644
--- a/tests/services/requests/test_requests_tasks.py
+++ b/tests/services/requests/test_requests_tasks.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 #
-# Copyright (C) 2022 Graz University of Technology.
+# Copyright (C) 2022-2025 Graz University of Technology.
 #
 # Invenio-Requests is free software; you can redistribute it and/or
 # modify it under the terms of the MIT License; see LICENSE file for more
@@ -8,7 +8,7 @@
 
 """Tasks tests."""
 
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 
 from invenio_access.permissions import system_identity
 from invenio_search.engine import dsl
@@ -21,7 +21,7 @@ def test_check_expired_requests(
     app, identity_simple, create_request, submit_request, requests_service
 ):
     """Test if the expired system field works as intended."""
-    now = datetime.utcnow()
+    now = datetime.now(timezone.utc)
 
     # created only should not be picked up
     created_request = create_request(