diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index daedca7..68b6cc0 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -647,4 +647,5 @@
 erpnext.patches.v12_0.set_default_for_add_taxes_from_item_tax_template
 erpnext.patches.v12_0.remove_denied_leaves_from_leave_ledger
 erpnext.patches.v12_0.update_price_or_product_discount
-erpnext.patches.v12_0.set_production_capacity_in_workstation
\ No newline at end of file
+erpnext.patches.v12_0.set_production_capacity_in_workstation
+erpnext.patches.v12_0.set_against_blanket_order_in_sales_and_purchase_order
\ No newline at end of file
diff --git a/erpnext/patches/v12_0/set_against_blanket_order_in_sales_and_purchase_order.py b/erpnext/patches/v12_0/set_against_blanket_order_in_sales_and_purchase_order.py
new file mode 100644
index 0000000..555d8ae
--- /dev/null
+++ b/erpnext/patches/v12_0/set_against_blanket_order_in_sales_and_purchase_order.py
@@ -0,0 +1,9 @@
+import frappe
+def execute():
+	for doctype in ['Sales Order Item', 'Purchase Order Item']:
+		frappe.reload_doctype(doctype)
+		frappe.db.sql("""
+			UPDATE `tab{0}`
+			SET against_blanket_order = 1
+			WHERE ifnull(blanket_order, '') != ''
+		""".format(doctype))