diff --git a/aplus/settings.py b/aplus/settings.py
index fb2f37afa..1882b5e3e 100644
--- a/aplus/settings.py
+++ b/aplus/settings.py
@@ -391,7 +391,6 @@
 ]
 TIME_ZONE = 'EET'
 USE_I18N = True
-USE_L10N = True
 USE_TZ = True
 FORMAT_MODULE_PATH = 'aplus'
 LOCALE_PATHS = (
diff --git a/edit_course/operations/clone.py b/edit_course/operations/clone.py
index fd13d9708..925a4ea77 100644
--- a/edit_course/operations/clone.py
+++ b/edit_course/operations/clone.py
@@ -1,5 +1,7 @@
 import logging
 
+from datetime import datetime
+from django.utils import timezone
 from django.db import transaction
 from django.contrib.auth.models import User
 from course.models import CourseInstance
@@ -34,8 +36,8 @@ def set_sis(instance: CourseInstance, id: str, enroll: bool) -> None: # pylint:
         return
 
     if coursedata.get('starting_time') and coursedata.get('ending_time'):
-        instance.starting_time = coursedata['starting_time']
-        instance.ending_time = coursedata['ending_time']
+        instance.starting_time = timezone.make_aware(datetime.strptime(coursedata['starting_time'], '%Y-%m-%d'))
+        instance.ending_time = timezone.make_aware(datetime.strptime(coursedata['ending_time'], '%Y-%m-%d'))
 
     instance.sis_id = id
     instance.sis_enroll = enroll
diff --git a/edit_course/tests.py b/edit_course/tests.py
index 63edae953..b080db479 100644
--- a/edit_course/tests.py
+++ b/edit_course/tests.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+import pytz
 from json import dumps
 from django.test import override_settings
 from course.models import CourseInstance
diff --git a/external_services/api/authentication.py b/external_services/api/authentication.py
index d5b7e89f3..41e3c60a8 100644
--- a/external_services/api/authentication.py
+++ b/external_services/api/authentication.py
@@ -54,12 +54,12 @@ def verify_oauth_body_hash_and_signature(request, req_body_hash, lti_exercise=No
 
     # check the OAuth timestamp. Do not allow old requests in order to prevent replay attacks.
     try:
-        timestamp = datetime.datetime.utcfromtimestamp(int(req_oauth_params_dict.get('oauth_timestamp')))
+        timestamp = datetime.datetime.fromtimestamp(int(req_oauth_params_dict.get('oauth_timestamp')), datetime.timezone.utc)
         # oauth_timestamp: seconds since January 1, 1970 00:00:00 GMT
     except ValueError:
         return False, 'oauth_timestamp is missing or has an invalid format'
 
-    now = datetime.datetime.utcnow()
+    now = datetime.datetime.now(datetime.timezone.utc)
     delta = datetime.timedelta(seconds=OAuthNonceCache.CACHE_TIMEOUT_SECONDS)
     if not (now - delta < timestamp and timestamp < now + delta): # pylint: disable=chained-comparison
         return False, 'oauth_timestamp has expired'