diff --git a/aleksis/apps/chronos/migrations/0007_advanced_models_from_untis.py b/aleksis/apps/chronos/migrations/0007_advanced_models_from_untis.py
index e7ae5fc039e9020716e69973159a92c2acd819c8..afca61fcb07d25dc2a6960c4833dc6dfa1f7f731 100644
--- a/aleksis/apps/chronos/migrations/0007_advanced_models_from_untis.py
+++ b/aleksis/apps/chronos/migrations/0007_advanced_models_from_untis.py
@@ -178,4 +178,19 @@ class Migration(migrations.Migration):
             model_name='absence',
             index=models.Index(fields=['date_start', 'date_end'], name='chronos_abs_date_st_337ff5_idx'),
         ),
+        migrations.AddField(
+            model_name='lessonsubstitution',
+            name='cancelled_for_teachers',
+            field=models.BooleanField(default=False, verbose_name='Cancelled for teachers?'),
+        ),
+        migrations.AddField(
+            model_name='lessonsubstitution',
+            name='comment',
+            field=models.TextField(blank=True, null=True, verbose_name='Comment'),
+        ),
+        migrations.AlterField(
+            model_name='lessonsubstitution',
+            name='cancelled',
+            field=models.BooleanField(default=False, verbose_name='Cancelled?'),
+        ),
     ]
diff --git a/aleksis/apps/chronos/models.py b/aleksis/apps/chronos/models.py
index 7e05735ede7a6642c1216fd28f4d9e0667372554..49b57d666d53290c07f08c581d6570729b704101 100644
--- a/aleksis/apps/chronos/models.py
+++ b/aleksis/apps/chronos/models.py
@@ -467,7 +467,10 @@ class LessonSubstitution(models.Model):
     )
     room = models.ForeignKey("Room", models.CASCADE, null=True, blank=True, verbose_name=_("Room"))
 
-    cancelled = models.BooleanField(default=False)
+    cancelled = models.BooleanField(default=False, verbose_name=_("Cancelled?"))
+    cancelled_for_teachers = models.BooleanField(default=False, verbose_name=_("Cancelled for teachers?"))
+
+    comment = models.TextField(verbose_name=_("Comment"), blank=True, null=True)
 
     def clean(self) -> None:
         if self.subject and self.cancelled:
@@ -667,6 +670,6 @@ class Event(ExtensibleModel):
 
     class Meta:
         ordering = ["date_start"]
-        indexes = [models.Index(fields=["periodfrom", "periodto", "date_start", "date_end"])]
+        indexes = [models.Index(fields=["period_from", "period_to", "date_start", "date_end"])]
         verbose_name = _("Event")
         verbose_name = _("Events")