diff --git a/src/c3nav/api/migrations/0002_django_4_0.py b/src/c3nav/api/migrations/0002_django_4_0.py
new file mode 100644
index 00000000..edb2cb22
--- /dev/null
+++ b/src/c3nav/api/migrations/0002_django_4_0.py
@@ -0,0 +1,21 @@
+# Generated by Django 4.0.3 on 2022-04-03 17:32
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('api', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='token',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
+        ),
+    ]
diff --git a/src/c3nav/control/migrations/0009_django_4_0.py b/src/c3nav/control/migrations/0009_django_4_0.py
new file mode 100644
index 00000000..6b921f08
--- /dev/null
+++ b/src/c3nav/control/migrations/0009_django_4_0.py
@@ -0,0 +1,37 @@
+# Generated by Django 4.0.3 on 2022-04-03 17:32
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('mapdata', '0086_django_4_0'),
+        ('control', '0008_userpermissions_reports'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='userpermissions',
+            name='review_group_reports',
+            field=models.ManyToManyField(blank=True, limit_choices_to={'access_restriction': None}, to='mapdata.locationgroup', verbose_name='can review reports belonging to'),
+        ),
+        migrations.AlterField(
+            model_name='userpermissions',
+            name='user',
+            field=models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, primary_key=True, serialize=False, to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AlterField(
+            model_name='userspaceaccess',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space'),
+        ),
+        migrations.AlterField(
+            model_name='userspaceaccess',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
+        ),
+    ]
diff --git a/src/c3nav/editor/migrations/0002_django_4_0.py b/src/c3nav/editor/migrations/0002_django_4_0.py
new file mode 100644
index 00000000..0efa9f7c
--- /dev/null
+++ b/src/c3nav/editor/migrations/0002_django_4_0.py
@@ -0,0 +1,47 @@
+# Generated by Django 4.0.3 on 2022-04-03 17:32
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('contenttypes', '0002_remove_content_type_name'),
+        ('editor', '0001_squashed_2018'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='changedobject',
+            name='changeset',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='editor.changeset', verbose_name='Change Set'),
+        ),
+        migrations.AlterField(
+            model_name='changedobject',
+            name='content_type',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='contenttypes.contenttype'),
+        ),
+        migrations.AlterField(
+            model_name='changedobject',
+            name='m2m_added',
+            field=models.JSONField(default=dict, verbose_name='added m2m values'),
+        ),
+        migrations.AlterField(
+            model_name='changedobject',
+            name='m2m_removed',
+            field=models.JSONField(default=dict, verbose_name='removed m2m values'),
+        ),
+        migrations.AlterField(
+            model_name='changedobject',
+            name='updated_fields',
+            field=models.JSONField(default=dict, verbose_name='updated fields'),
+        ),
+        migrations.AlterField(
+            model_name='changeset',
+            name='author',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL, verbose_name='Author'),
+        ),
+    ]
diff --git a/src/c3nav/editor/models/changedobject.py b/src/c3nav/editor/models/changedobject.py
index bb6e6974..db73cbe4 100644
--- a/src/c3nav/editor/models/changedobject.py
+++ b/src/c3nav/editor/models/changedobject.py
@@ -9,7 +9,7 @@ from django.db.models import CharField, DecimalField, Field, TextField
 from django.utils.translation import gettext_lazy as _
 
 from c3nav.editor.wrappers import ModelInstanceWrapper, is_created_pk
-from c3nav.mapdata.fields import I18nField, JSONField
+from c3nav.mapdata.fields import I18nField
 from c3nav.mapdata.models.locations import LocationRedirect
 
 
@@ -35,9 +35,9 @@ class ChangedObject(models.Model):
     created = models.DateTimeField(auto_now_add=True, verbose_name=_('created'))
     content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
     existing_object_pk = models.PositiveIntegerField(null=True, verbose_name=_('id of existing object'))
-    updated_fields = JSONField(default={}, verbose_name=_('updated fields'))
-    m2m_added = JSONField(default={}, verbose_name=_('added m2m values'))
-    m2m_removed = JSONField(default={}, verbose_name=_('removed m2m values'))
+    updated_fields = models.JSONField(default=dict, verbose_name=_('updated fields'))
+    m2m_added = models.JSONField(default=dict, verbose_name=_('added m2m values'))
+    m2m_removed = models.JSONField(default=dict, verbose_name=_('removed m2m values'))
     deleted = models.BooleanField(default=False, verbose_name=_('object was deleted'))
 
     objects = ChangedObjectManager()
diff --git a/src/c3nav/mapdata/fields.py b/src/c3nav/mapdata/fields.py
index 59cd7590..19a37fc0 100644
--- a/src/c3nav/mapdata/fields.py
+++ b/src/c3nav/mapdata/fields.py
@@ -31,7 +31,7 @@ def validate_geometry(geometry: BaseGeometry):
 shapely_logger = logging.getLogger('shapely.geos')
 
 
-class GeometryField(models.TextField):
+class GeometryField(models.JSONField):
     default_validators = [validate_geometry]
 
     def __init__(self, geomtype=None, default=None, null=False):
@@ -50,9 +50,7 @@ class GeometryField(models.TextField):
         return name, path, args, kwargs
 
     def from_db_value(self, value, expression, connection):
-        if value is None:
-            return value
-        return WrappedGeometry(json.loads(value))
+        return WrappedGeometry(super().from_db_value(value, expression, connection))
 
     def to_python(self, value):
         if value is None or value == '':
@@ -117,6 +115,7 @@ class GeometryField(models.TextField):
 
 
 class JSONField(models.TextField):
+    # Deprecated
     def from_db_value(self, value, expression, connection):
         if value is None:
             return value
@@ -173,7 +172,7 @@ class I18nDescriptor:
         setattr(instance, self.field.attname, value)
 
 
-class I18nField(JSONField):
+class I18nField(models.JSONField):
     def __init__(self, verbose_name=None, plural_name=None, max_length=None, default=None,
                  fallback_language=settings.LANGUAGE_CODE, fallback_any=False, fallback_value=None, **kwargs):
         self.i18n_max_length = max_length
@@ -182,7 +181,7 @@ class I18nField(JSONField):
         self.fallback_any = fallback_any
         self.fallback_value = fallback_value
         kwargs.pop('null', None)
-        super().__init__(verbose_name=verbose_name, default=(dict(default) if default else {}), null=False, **kwargs)
+        super().__init__(verbose_name=verbose_name, default=(dict(default) if default else dict), null=False, **kwargs)
 
     def get_default(self):
         return self.default.copy()
diff --git a/src/c3nav/mapdata/migrations/0086_django_4_0.py b/src/c3nav/mapdata/migrations/0086_django_4_0.py
new file mode 100644
index 00000000..6e264fd3
--- /dev/null
+++ b/src/c3nav/mapdata/migrations/0086_django_4_0.py
@@ -0,0 +1,316 @@
+# Generated by Django 4.0.3 on 2022-04-03 17:32
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('mapdata', '0085_locationgroupcategory_allow_dynamic_locations'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='accesspermission',
+            name='access_restriction',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.accessrestriction'),
+        ),
+        migrations.AlterField(
+            model_name='accesspermission',
+            name='token',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, to='mapdata.accesspermissiontoken', verbose_name='Access permission token'),
+        ),
+        migrations.AlterField(
+            model_name='accesspermission',
+            name='user',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AlterField(
+            model_name='accessrestriction',
+            name='groups',
+            field=models.ManyToManyField(blank=True, to='mapdata.accessrestrictiongroup', verbose_name='Groups'),
+        ),
+        migrations.AlterField(
+            model_name='altitudearea',
+            name='level',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.level', verbose_name='level'),
+        ),
+        migrations.AlterField(
+            model_name='altitudemarker',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='area',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='area',
+            name='groups',
+            field=models.ManyToManyField(blank=True, to='mapdata.locationgroup', verbose_name='Location Groups'),
+        ),
+        migrations.AlterField(
+            model_name='area',
+            name='label_settings',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.labelsettings', verbose_name='label settings'),
+        ),
+        migrations.AlterField(
+            model_name='area',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='area',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='building',
+            name='level',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.level', verbose_name='level'),
+        ),
+        migrations.AlterField(
+            model_name='column',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='column',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='crossdescription',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='door',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='door',
+            name='level',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.level', verbose_name='level'),
+        ),
+        migrations.AlterField(
+            model_name='dynamiclocation',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='dynamiclocation',
+            name='groups',
+            field=models.ManyToManyField(blank=True, to='mapdata.locationgroup', verbose_name='Location Groups'),
+        ),
+        migrations.AlterField(
+            model_name='dynamiclocation',
+            name='label_settings',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.labelsettings', verbose_name='label settings'),
+        ),
+        migrations.AlterField(
+            model_name='dynamiclocation',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='graphedge',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='graphedge',
+            name='waytype',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.waytype', verbose_name='Way Type'),
+        ),
+        migrations.AlterField(
+            model_name='graphnode',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='hole',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='leavedescription',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='level',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='level',
+            name='groups',
+            field=models.ManyToManyField(blank=True, to='mapdata.locationgroup', verbose_name='Location Groups'),
+        ),
+        migrations.AlterField(
+            model_name='level',
+            name='label_settings',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.labelsettings', verbose_name='label settings'),
+        ),
+        migrations.AlterField(
+            model_name='level',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='lineobstacle',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='locationgroup',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='locationgroup',
+            name='label_settings',
+            field=models.ForeignKey(blank=True, help_text='unless location specifies otherwise', null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.labelsettings', verbose_name='label settings'),
+        ),
+        migrations.AlterField(
+            model_name='locationgroup',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='locationredirect',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='mapupdate',
+            name='user',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AlterField(
+            model_name='obstacle',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='poi',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='poi',
+            name='groups',
+            field=models.ManyToManyField(blank=True, to='mapdata.locationgroup', verbose_name='Location Groups'),
+        ),
+        migrations.AlterField(
+            model_name='poi',
+            name='label_settings',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.labelsettings', verbose_name='label settings'),
+        ),
+        migrations.AlterField(
+            model_name='poi',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='poi',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='position',
+            name='coordinates_id',
+            field=models.CharField(blank=True, max_length=48, null=True, verbose_name='coordinates'),
+        ),
+        migrations.AlterField(
+            model_name='position',
+            name='owner',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AlterField(
+            model_name='position',
+            name='timeout',
+            field=models.PositiveSmallIntegerField(blank=True, default=0, help_text='0 for no timeout', verbose_name='timeout (in seconds)'),
+        ),
+        migrations.AlterField(
+            model_name='ramp',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='report',
+            name='author',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL, verbose_name='author'),
+        ),
+        migrations.AlterField(
+            model_name='report',
+            name='created_groups',
+            field=models.ManyToManyField(blank=True, help_text='select all groups that apply, if any', limit_choices_to={'can_report_missing': True}, related_name='+', to='mapdata.locationgroup', verbose_name='location groups'),
+        ),
+        migrations.AlterField(
+            model_name='reportupdate',
+            name='author',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL, verbose_name='author'),
+        ),
+        migrations.AlterField(
+            model_name='reportupdate',
+            name='open',
+            field=models.BooleanField(null=True, verbose_name='open'),
+        ),
+        migrations.AlterField(
+            model_name='source',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='space',
+            name='access_restriction',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.accessrestriction', verbose_name='Access Restriction'),
+        ),
+        migrations.AlterField(
+            model_name='space',
+            name='groups',
+            field=models.ManyToManyField(blank=True, to='mapdata.locationgroup', verbose_name='Location Groups'),
+        ),
+        migrations.AlterField(
+            model_name='space',
+            name='label_settings',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to='mapdata.labelsettings', verbose_name='label settings'),
+        ),
+        migrations.AlterField(
+            model_name='space',
+            name='level',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.level', verbose_name='level'),
+        ),
+        migrations.AlterField(
+            model_name='space',
+            name='locationslug_ptr',
+            field=models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='mapdata.locationslug'),
+        ),
+        migrations.AlterField(
+            model_name='stair',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+        migrations.AlterField(
+            model_name='wifimeasurement',
+            name='author',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL, verbose_name='author'),
+        ),
+        migrations.AlterField(
+            model_name='wifimeasurement',
+            name='data',
+            field=models.JSONField(verbose_name='Measurement list'),
+        ),
+        migrations.AlterField(
+            model_name='wifimeasurement',
+            name='space',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='mapdata.space', verbose_name='space'),
+        ),
+    ]
diff --git a/src/c3nav/mapdata/models/geometry/space.py b/src/c3nav/mapdata/models/geometry/space.py
index 29263e93..112fadf4 100644
--- a/src/c3nav/mapdata/models/geometry/space.py
+++ b/src/c3nav/mapdata/models/geometry/space.py
@@ -10,7 +10,7 @@ from django.utils.text import format_lazy
 from django.utils.translation import gettext_lazy as _
 from shapely.geometry import CAP_STYLE, JOIN_STYLE, mapping
 
-from c3nav.mapdata.fields import GeometryField, I18nField, JSONField
+from c3nav.mapdata.fields import GeometryField, I18nField
 from c3nav.mapdata.grid import grid
 from c3nav.mapdata.models import Space
 from c3nav.mapdata.models.access import AccessRestrictionMixin
@@ -384,7 +384,7 @@ class WifiMeasurement(SpaceGeometryMixin, models.Model):
     author = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True, blank=True,
                                verbose_name=_('author'))
     comment = models.TextField(null=True, blank=True, verbose_name=_('comment'))
-    data = JSONField(_('Measurement list'))
+    data = models.JSONField(_('Measurement list'))
 
     class Meta:
         verbose_name = _('Wi-Fi Measurement')
diff --git a/src/c3nav/routing/migrations/0002_django_4_0.py b/src/c3nav/routing/migrations/0002_django_4_0.py
new file mode 100644
index 00000000..d8e775ae
--- /dev/null
+++ b/src/c3nav/routing/migrations/0002_django_4_0.py
@@ -0,0 +1,26 @@
+# Generated by Django 4.0.3 on 2022-04-03 17:32
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('routing', '0001_routeoptions'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='routeoptions',
+            name='data',
+            field=models.JSONField(default=dict),
+        ),
+        migrations.AlterField(
+            model_name='routeoptions',
+            name='user',
+            field=models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, primary_key=True, serialize=False, to=settings.AUTH_USER_MODEL),
+        ),
+    ]
diff --git a/src/c3nav/routing/models.py b/src/c3nav/routing/models.py
index f66cf910..390e85fb 100644
--- a/src/c3nav/routing/models.py
+++ b/src/c3nav/routing/models.py
@@ -8,13 +8,12 @@ from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.translation import gettext_lazy as _
 
-from c3nav.mapdata.fields import JSONField
 from c3nav.mapdata.models import MapUpdate, WayType
 
 
 class RouteOptions(models.Model):
     user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, primary_key=True)
-    data = JSONField(default={})
+    data = models.JSONField(default=dict)
 
     class Meta:
         verbose_name = _('Route options')
diff --git a/src/c3nav/site/migrations/0006_django_4_0.py b/src/c3nav/site/migrations/0006_django_4_0.py
new file mode 100644
index 00000000..5252b2c5
--- /dev/null
+++ b/src/c3nav/site/migrations/0006_django_4_0.py
@@ -0,0 +1,21 @@
+# Generated by Django 4.0.3 on 2022-04-03 17:32
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('site', '0005_siteupdate_default_related_name'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='announcement',
+            name='author',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL, verbose_name='author'),
+        ),
+    ]