expected delivery date mandatory only if order type is sales
diff --git a/erpnext/selling/doctype/sales_order/sales_order.py b/erpnext/selling/doctype/sales_order/sales_order.py
index 9e76327..660a288 100644
--- a/erpnext/selling/doctype/sales_order/sales_order.py
+++ b/erpnext/selling/doctype/sales_order/sales_order.py
@@ -286,7 +286,7 @@
 	#-----------------------------------------------------------------------------------------------
 	def validate_order_type(self):
 		#validate delivery date
-		if self.doc.order_type != 'Maintenance' and not self.doc.delivery_date:
+		if self.doc.order_type == 'Sales' and not self.doc.delivery_date:
 			msgprint("Please enter 'Expected Delivery Date'")
 			raise Exception