diff --git a/erpnext/patches/may_2012/rename_prev_doctype.py b/erpnext/patches/may_2012/rename_prev_doctype.py
new file mode 100644
index 0000000..162fb04
--- /dev/null
+++ b/erpnext/patches/may_2012/rename_prev_doctype.py
@@ -0,0 +1,14 @@
+def execute():
+	import webnotes
+	dt_list = webnotes.conn.sql("select parent, fieldname from `tabDocField` where fieldname in ('against_doctype', 'prevdoc_doctype')")
+	
+	ren_dt = {
+		'Indent' : 'Purchase Request',
+		'Enquiry' : 'Opportunity',
+		'Receivable Voucher' : 'Sales Invoice',
+		'Payable Voucher' : 'Purchase Invoice'
+	}
+
+	for d in ren_dt:
+		for dt in dt_list: 
+			webnotes.conn.sql("update `tab%s` set %s = '%s' where %s = '%s'" % (dt[0], dt[1], ren_dt[d], dt[1], d))