Multibuys only work with POS invoices. If this feature was extended to work in quotations, sales orders and sales invoices, the pricing module would be much more powerful.
This is not the issue of upgrade SERP. But serverip.dat in this case contains the value: 192.168.88.12:1301, so this is local IP of the server with SERP.
Anyway I don't understand what do you me...
