diff --git a/gtfs_loader/schema.py b/gtfs_loader/schema.py
index 63be236..d265ca4 100644
--- a/gtfs_loader/schema.py
+++ b/gtfs_loader/schema.py
@@ -95,11 +95,11 @@ class BookingRule(Entity):
 
     booking_rule_id: str
     booking_type: BookingType
-    prior_notice_duration_min: int = 0
-    prior_notice_duration_max: int = 0
-    prior_notice_last_day: int = 0
+    prior_notice_duration_min: Optional[int] = None
+    prior_notice_duration_max: Optional[int] = None
+    prior_notice_last_day: Optional[int] = None
     prior_notice_last_time: GTFSTime = GTFSTime('')
-    prior_notice_start_day: int = 0
+    prior_notice_start_day: Optional[int] = None
     prior_notice_start_time: GTFSTime = GTFSTime('')
     prior_notice_service_id: str = ''
     message: str = ''
diff --git a/setup.py b/setup.py
index ff7414d..12998f5 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
 from setuptools import setup, find_packages
 
 setup(name='py-gtfs-loader',
-      version='0.1.5',
+      version='0.1.6',
       description='Load GTFS',
       url='https://github.com/TransitApp/py-gtfs-loader',
       author='Nicholas Paun, Jonathan Milot',