diff --git a/aleksis/apps/chronos/migrations/0014_add_managed_by_app_label.py b/aleksis/apps/chronos/migrations/0015_add_managed_by_app_label.py
similarity index 98%
rename from aleksis/apps/chronos/migrations/0014_add_managed_by_app_label.py
rename to aleksis/apps/chronos/migrations/0015_add_managed_by_app_label.py
index 79d10ea3564cf1f3043f411d39461d31b0f294cc..d4906fcd7eefb3fffd36136c75fa8d4feee76cc8 100644
--- a/aleksis/apps/chronos/migrations/0014_add_managed_by_app_label.py
+++ b/aleksis/apps/chronos/migrations/0015_add_managed_by_app_label.py
@@ -9,7 +9,7 @@ class Migration(migrations.Migration):
 
     dependencies = [
         ('sites', '0002_alter_domain_unique'),
-        ('chronos', '0013_move_room_to_core'),
+        ('chronos', '0014_lessonevent'),
     ]
 
     operations = [
diff --git a/aleksis/apps/chronos/migrations/0015_managed_by_site.py b/aleksis/apps/chronos/migrations/0015_managed_by_site.py
deleted file mode 100644
index 001528f86f0b981003a27b32558df0f25ea5f1e3..0000000000000000000000000000000000000000
--- a/aleksis/apps/chronos/migrations/0015_managed_by_site.py
+++ /dev/null
@@ -1,390 +0,0 @@
-# Generated by Django 4.2.3 on 2023-07-31 08:21
-
-import aleksis.core.managers
-from django.db import migrations, models
-import django.db.models.deletion
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ("sites", "0002_alter_domain_unique"),
-        ("chronos", "0014_lessonevent"),
-    ]
-
-    operations = [
-        migrations.AlterModelManagers(
-            name="absencereason",
-            managers=[
-                ("objects", aleksis.core.managers.AlekSISBaseManager()),
-            ],
-        ),
-        migrations.AlterModelManagers(
-            name="automaticplan",
-            managers=[],
-        ),
-        migrations.AlterModelManagers(
-            name="subject",
-            managers=[
-                ("objects", aleksis.core.managers.AlekSISBaseManager()),
-            ],
-        ),
-        migrations.AlterModelManagers(
-            name="supervisionarea",
-            managers=[
-                ("objects", aleksis.core.managers.AlekSISBaseManager()),
-            ],
-        ),
-        migrations.AddField(
-            model_name="absence",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="absencereason",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="break",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="event",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="exam",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="extralesson",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="holiday",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="lesson",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="lessonperiod",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="lessonsubstitution",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="subject",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="supervision",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="supervisionarea",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="supervisionsubstitution",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="timeperiod",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AddField(
-            model_name="validityrange",
-            name="managed_by_app_label",
-            field=models.CharField(
-                blank=True,
-                editable=False,
-                max_length=255,
-                verbose_name="App label of app responsible for managing this instance",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="absence",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="absencereason",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="break",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="event",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="exam",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="extralesson",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="holiday",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="lesson",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="lessonperiod",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="lessonsubstitution",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="subject",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="supervision",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="supervisionarea",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="supervisionsubstitution",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="timeperiod",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="timeperiod",
-            name="weekday",
-            field=models.PositiveSmallIntegerField(
-                choices=[
-                    (0, "Monday"),
-                    (1, "Tuesday"),
-                    (2, "Wednesday"),
-                    (3, "Thursday"),
-                    (4, "Friday"),
-                    (5, "Saturday"),
-                    (6, "Sunday"),
-                ],
-                verbose_name="Week day",
-            ),
-        ),
-        migrations.AlterField(
-            model_name="validityrange",
-            name="site",
-            field=models.ForeignKey(
-                default=1,
-                editable=False,
-                on_delete=django.db.models.deletion.CASCADE,
-                related_name="+",
-                to="sites.site",
-            ),
-        ),
-    ]