diff --git a/aleksis/apps/alsijil/schema/__init__.py b/aleksis/apps/alsijil/schema/__init__.py
index 4be2322de6e3c855fa1439c28aa07e2e4db09927..66d5216cc4aa8c4f3e702576f763ce808501a827 100644
--- a/aleksis/apps/alsijil/schema/__init__.py
+++ b/aleksis/apps/alsijil/schema/__init__.py
@@ -363,7 +363,7 @@ class Query(graphene.ObjectType):
 
     @staticmethod
     def resolve_periods(root, info):
-        if apps.is_installed("aleksis.app.lesrooster"):
+        if apps.is_installed("aleksis.apps.lesrooster"):
             Slot = apps.get_model("lesrooster", "Slot")
             ValidityRange = apps.get_model("lesrooster", "ValidityRange")
             slots = Slot.objects.filter(time_grid__validity_range=ValidityRange.current).order_by("weekday").values("weekday", "period", "time_start", "time_end")