diff --git a/shiftregister/app/models.py b/shiftregister/app/models.py
index f4315fc..49a4383 100644
--- a/shiftregister/app/models.py
+++ b/shiftregister/app/models.py
@@ -34,8 +34,8 @@ class Shift(models.Model):
                 Case(
                     When(
                         shiftregistration__state__in=[
-                            ShiftRegistration.REGISTERED,
-                            ShiftRegistration.CHECKED_IN,
+                            ShiftRegistration.RegState.REGISTERED,
+                            ShiftRegistration.RegState.CHECKED_IN,
                         ],
                         then=1,
                     ),
@@ -55,7 +55,10 @@ class Shift(models.Model):
 
     def registration_count(self):
         return self.shiftregistration_set.filter(
-            state__in=[ShiftRegistration.REGISTERED, ShiftRegistration.CHECKED_IN]
+            state__in=[
+                ShiftRegistration.RegState.REGISTERED,
+                ShiftRegistration.RegState.CHECKED_IN,
+            ]
         ).count()
 
 
@@ -86,7 +89,10 @@ class Helper(models.Model):
                 helper=self,
                 shift_end__gte=timezone.now(),
                 shift__deleted=False,
-                state__in=[ShiftRegistration.REGISTERED, ShiftRegistration.CHECKED_IN],
+                state__in=[
+                    ShiftRegistration.RegState.REGISTERED,
+                    ShiftRegistration.RegState.CHECKED_IN,
+                ],
             )
             .order_by("shift__start_at")
             .first()
@@ -104,24 +110,19 @@ class ShiftRegistration(models.Model):
     helper = models.ForeignKey(Helper, on_delete=models.CASCADE)
     reminder_sent = models.BooleanField(default=False)
 
-    # default is registered
-    REGISTERED = "REG"
-    CHECKED_IN = "CHECK"
-    # cancel via infopoint
-    CANCELED = "CANCEL"
-    # did not attend shift
-    FAILED = "FAIL"
+    class RegState(models.TextChoices):
+        # default is registered
+        REGISTERED = "REG", "registriert"
+        CHECKED_IN = "CHECK", "checkin"
+        # cancel via infopoint
+        CANCELED = "CANCEL", "abgemeldet"
+        # did not attend shift
+        FAILED = "FAIL", "nicht angetreten"
 
-    STATE_CHOICES = [
-        (REGISTERED, "registriert"),
-        (CHECKED_IN, "checkin"),
-        (CANCELED, "abgemeldet"),
-        (FAILED, "nicht angetreten"),
-    ]
     state = models.CharField(
         max_length=7,
-        choices=STATE_CHOICES,
-        default=REGISTERED,
+        choices=RegState.choices,
+        default=RegState.REGISTERED,
     )
 
     def can_cancel(self):
diff --git a/shiftregister/app/views.py b/shiftregister/app/views.py
index 9f12119..b02d95b 100644
--- a/shiftregister/app/views.py
+++ b/shiftregister/app/views.py
@@ -28,7 +28,10 @@ def index(request):
             reg.shift
             for reg in request.helper.shiftregistration_set.filter(
                 shift__start_at__gt=timezone.now(),
-                state__in=[ShiftRegistration.REGISTERED, ShiftRegistration.CHECKED_IN],
+                state__in=[
+                    ShiftRegistration.RegState.REGISTERED,
+                    ShiftRegistration.RegState.CHECKED_IN,
+                ],
             ).order_by("shift__start_at")
         )