Can I update Manual Invoices via API?

Invoices

You can fetch the details of Invoices.

 

Subscriptions

You can fetch the details of subscriptions and get data back about collection method('manual', 'automatic'), PO Number (string), and Net-terms (number, 0 for On Receipt).

You can also create subscriptions as normal in addition to being able to update the collection_method, po_number, and net_terms (update can not change the manual payment fields).