ISBN Question

I’m helping a friend get his novel ready for release, and he recently applied in New Zealand (where he lives) for ISBNs for the paperback, ebook, and audiobook formats. However, they ended up giving him two different ISBNs for ebooks: “Kindle” and “Epub.”

QUESTION: Since Amazon KDP now accepts Epub files for Kindle, should we still use the “Kindle” ISBN or just use the Epub ISBN on Amazon KDP and D2D (i.e., for all ebook sales locations)?

Unrelated to the question, if anyone’s interested, here’s a pic of the cover: