diff --git a/alyx/alyx/settings_lab_template.py b/alyx/alyx/settings_lab_template.py
index 8d3bfc49..4f8ac7a8 100644
--- a/alyx/alyx/settings_lab_template.py
+++ b/alyx/alyx/settings_lab_template.py
@@ -3,7 +3,7 @@
 # ALYX-SPECIFIC
 ALLOWED_HOSTS = ['localhost', '127.0.0.1']
 LANGUAGE_CODE = 'en-us'
-TIME_ZONE = 'GB'
+TIME_ZONE = 'Europe/London'
 GLOBUS_CLIENT_ID = '525cc543-8ccb-4d11-8036-af332da5eafd'
 SUBJECT_REQUEST_EMAIL_FROM = 'alyx@internationalbrainlab.org'
 DEFAULT_SOURCE = 'IBL'
diff --git a/alyx/data/migrations/0020_alter_datarepository_timezone.py b/alyx/data/migrations/0020_alter_datarepository_timezone.py
new file mode 100644
index 00000000..3dd45bcc
--- /dev/null
+++ b/alyx/data/migrations/0020_alter_datarepository_timezone.py
@@ -0,0 +1,23 @@
+# Generated by Django 5.0 on 2024-03-26 15:27
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("data", "0019_dataset_qc"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="datarepository",
+            name="timezone",
+            field=models.CharField(
+                blank=True,
+                default="Europe/London",
+                help_text="Timezone of the server (see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)",
+                max_length=64,
+            ),
+        ),
+    ]
diff --git a/alyx/experiments/serializers.py b/alyx/experiments/serializers.py
index 92ad06a8..9e72f688 100644
--- a/alyx/experiments/serializers.py
+++ b/alyx/experiments/serializers.py
@@ -46,15 +46,6 @@ class TrajectoryEstimateSerializer(serializers.ModelSerializer):
         queryset=CoordinateSystem.objects.all(),
     )
 
-    def to_internal_value(self, data):
-        if data.get('chronic_insertion', None) is None:
-            data['chronic_insertion'] = None
-
-        if data.get('probe_insertion', None) is None:
-            data['probe_insertion'] = None
-
-        return super(TrajectoryEstimateSerializer, self).to_internal_value(data)
-
     class Meta:
         model = TrajectoryEstimate
         fields = '__all__'
diff --git a/alyx/experiments/tests_rest.py b/alyx/experiments/tests_rest.py
index c2138d1e..412a4a6b 100644
--- a/alyx/experiments/tests_rest.py
+++ b/alyx/experiments/tests_rest.py
@@ -185,6 +185,7 @@ def test_create_list_delete_trajectory(self):
         # create a trajectory
         url = reverse('trajectoryestimate-list')
         tdict = {'probe_insertion': alyx_insertion['id'],
+                 'chronic_insertion': None,
                  'x': -4521.2,
                  'y': 2415.0,
                  'z': 0,
@@ -216,6 +217,7 @@ def test_create_list_delete_channels(self):
         # create the probe insertion
         pi = self.ar(self.post(reverse('probeinsertion-list'), self.dict_insertion), 201)
         tdict = {'probe_insertion': pi['id'],
+                 'chronic_insertion': None,
                  'x': -4521.2,
                  'y': 2415.0,
                  'z': 0,
@@ -273,6 +275,7 @@ def test_chronic_insertion(self):
 
         # create a trajectory and attach it to the chronic insertion
         traj_dict = {'chronic_insertion': ci['id'],
+                     'probe_insertion': None,
                      'x': -4521.2,
                      'y': 2415.0,
                      'z': 0,
diff --git a/alyx/misc/migrations/0010_alter_lab_timezone.py b/alyx/misc/migrations/0010_alter_lab_timezone.py
new file mode 100644
index 00000000..3d789c58
--- /dev/null
+++ b/alyx/misc/migrations/0010_alter_lab_timezone.py
@@ -0,0 +1,23 @@
+# Generated by Django 5.0 on 2024-03-26 15:27
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("misc", "0009_auto_20211122_1535"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="lab",
+            name="timezone",
+            field=models.CharField(
+                blank=True,
+                default="Europe/London",
+                help_text="Timezone of the server (see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)",
+                max_length=64,
+            ),
+        ),
+    ]
diff --git a/requirements_frozen.txt b/requirements_frozen.txt
index c3d0b179..b4dfc7f1 100644
--- a/requirements_frozen.txt
+++ b/requirements_frozen.txt
@@ -1,7 +1,7 @@
 asgiref==3.8.1
 backports.zoneinfo==0.2.1
-boto3==1.34.69
-botocore==1.34.69
+boto3==1.34.70
+botocore==1.34.70
 certifi==2024.2.2
 cffi==1.16.0
 charset-normalizer==3.3.2