diff --git a/db/migrate/20190314084909_object_manager_attribute_date_remove_future_past.rb b/db/migrate/20190314084909_object_manager_attribute_date_remove_future_past.rb
index 47df6274a..8e3a4e07a 100644
--- a/db/migrate/20190314084909_object_manager_attribute_date_remove_future_past.rb
+++ b/db/migrate/20190314084909_object_manager_attribute_date_remove_future_past.rb
@@ -6,6 +6,12 @@ class ObjectManagerAttributeDateRemoveFuturePast < ActiveRecord::Migration[5.1]
 
     ObjectManager::Attribute.where(data_type: 'date').each do |attribute|
       attribute.data_option = attribute.data_option.except(:future, :past)
+
+      # some attributes from the early Zammad days don't have all
+      # required data_option attributes because they were not properly migrated
+      # so we need to fix them now
+      attribute.data_option[:diff] ||= 24
+
       attribute.save!
     end
   end
diff --git a/spec/db/migrate/object_manager_attribute_date_remove_future_past_spec.rb b/spec/db/migrate/object_manager_attribute_date_remove_future_past_spec.rb
index 779e4ceac..f6a9cdde8 100644
--- a/spec/db/migrate/object_manager_attribute_date_remove_future_past_spec.rb
+++ b/spec/db/migrate/object_manager_attribute_date_remove_future_past_spec.rb
@@ -21,5 +21,29 @@ RSpec.describe ObjectManagerAttributeDateRemoveFuturePast, type: :db_migration d
 
       expect(subject.data_option).to_not include(:past, :future)
     end
+
+    context 'when incomplete data_option is given' do
+
+      it 'adds missing :diff option' do
+        subject = build(:object_manager_attribute_date)
+
+        # add data_options manually because the factory doesn't contain them anymore
+        subject.data_option = subject.data_option.merge(
+          future: false,
+          past:   false,
+        )
+
+        # remove diff option as for some attributes
+        # from older Zammad installations
+        subject.data_option.delete(:diff)
+
+        # mock interfaces to save time
+        # otherwise we would have to reseed the database
+        expect(ObjectManager::Attribute).to receive(:where).and_return([subject])
+        # expect(subject).to receive(:save!)
+
+        expect { migrate }.not_to raise_error
+      end
+    end
   end
 end