diff --git a/erpnext/__version__.py b/erpnext/__version__.py
index f863722c26f..0f031cb2a5f 100644
--- a/erpnext/__version__.py
+++ b/erpnext/__version__.py
@@ -1,2 +1,2 @@
 from __future__ import unicode_literals
-__version__ = '6.4.5'
+__version__ = '6.4.6'
diff --git a/erpnext/hooks.py b/erpnext/hooks.py
index ec8d4b5eae9..90478c51e6a 100644
--- a/erpnext/hooks.py
+++ b/erpnext/hooks.py
@@ -29,7 +29,7 @@ blogs.
 """
 app_icon = "icon-th"
 app_color = "#e74c3c"
-app_version = "6.4.5"
+app_version = "6.4.6"
 github_link = "https://github.com/frappe/erpnext"
 
 error_report_email = "support@erpnext.com"
diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index 9eaa0121daf..85bf3cb1315 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -215,3 +215,4 @@ erpnext.patches.v6_4.round_status_updater_percentages
 erpnext.patches.v6_4.repost_gle_for_journal_entries_where_reference_name_missing
 erpnext.patches.v6_4.fix_journal_entries_due_to_reconciliation
 erpnext.patches.v6_4.fix_status_in_sales_and_purchase_order
+erpnext.patches.v6_4.fix_modified_in_sales_order_and_purchase_order
\ No newline at end of file
diff --git a/erpnext/patches/v6_4/fix_modified_in_sales_order_and_purchase_order.py b/erpnext/patches/v6_4/fix_modified_in_sales_order_and_purchase_order.py
new file mode 100644
index 00000000000..f27489e7b01
--- /dev/null
+++ b/erpnext/patches/v6_4/fix_modified_in_sales_order_and_purchase_order.py
@@ -0,0 +1,10 @@
+from __future__ import unicode_literals
+import frappe
+
+def execute():
+	for doctype in ("Sales Order", "Purchase Order"):
+		data = frappe.db.sql("""select parent, modified_by, modified
+			from `tab{doctype} Item` where docstatus=1 group by parent""".format(doctype=doctype), as_dict=True)
+		for item in data:
+			frappe.db.sql("""update `tab{doctype}` set modified_by=%(modified_by)s, modified=%(modified)s
+				where name=%(parent)s""".format(doctype=doctype), item)
diff --git a/setup.py b/setup.py
index 7670f39b05c..770c45d0246 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 from setuptools import setup, find_packages
 
-version = "6.4.5"
+version = "6.4.6"
 
 with open("requirements.txt", "r") as f:
 	install_requires = f.readlines()