The same April–March year as India, and no e-invoicing mandate.
New Zealand is the lowest-effort market on this list to support fully, for two reasons that happen to line up. The tax year runs 1 April to 31 March — identical to India — so every fiscal-period assumption in the product is already correct. And there is no e-invoicing mandate, so nothing has to be built before invoices can be issued. What remains unbuilt is GST return preparation itself, which is a form rather than a clearance integration. For a New Zealand contractor the gap between what works and what is missing is smaller here than anywhere else outside India.
This page is the intersection. The country page covers currency, financial year and statutory position in detail; the sector page covers what is built, the turnover bands it suits, and what is missing regardless of country.