diff --git a/shiftregister/importer/dynamic_preferences_registry.py b/shiftregister/importer/dynamic_preferences_registry.py
new file mode 100644
index 0000000..dcf9820
--- /dev/null
+++ b/shiftregister/importer/dynamic_preferences_registry.py
@@ -0,0 +1,14 @@
+import datetime
+
+from dynamic_preferences import types
+from dynamic_preferences.registries import global_preferences_registry
+
+_import = types.Section("import")
+
+
+@global_preferences_registry.register
+class NotBefore(types.DatePreference):
+    section = _import
+    name = "not_before"
+    default = datetime.date.today()
+    help_text = "Do not import shifts ending before this date"
diff --git a/shiftregister/importer/importer.py b/shiftregister/importer/importer.py
index 9451f6c..94d663a 100644
--- a/shiftregister/importer/importer.py
+++ b/shiftregister/importer/importer.py
@@ -3,10 +3,13 @@ from datetime import timezone
 import requests
 from django.conf import settings
 from django.db import transaction
+from dynamic_preferences.registries import global_preferences_registry
 from icalendar import Calendar
 
 from .models import Event, Room, Shift
 
+global_preferences = global_preferences_registry.manager()
+
 
 def import_calendar(calendar):
     try:
@@ -20,6 +23,8 @@ def import_calendar(calendar):
     if not r.headers["content-type"].startswith("text/calendar"):
         return False
 
+    not_before = global_preferences["import__not_before"]
+
     try:
         cal = Calendar.from_ical(r.text)
 
@@ -32,8 +37,10 @@ def import_calendar(calendar):
             start = event.decoded("dtstart").astimezone(timezone.utc)
             end = event.decoded("dtend").astimezone(timezone.utc)
             location = event.decoded("location", None)
-            if not summary:
+
+            if not summary or end.date() < not_before:
                 continue
+
             if location is not None:
                 location = location.decode().strip()