I've updated database directly to make is_required on lastname = 0.
Removed the js validator for lastname in core.
Removed required field in frontend in widget/name.phtml.
However, The "Last name is required field" message still popups in 3 places:
During onepage checkout
When creating an order in admin for billing/shipping address
When inputing billing/shipping address for a customer in admin
Could some one help me please? We're doing wholesale and use only Purchase Order and COD. Thus, customer normally only puts in their outlet name in First Name field. Last Name is just optional for them.
Best Answer
To make field Last Name none required for Customer editing in admin create sql upgrade script