Kindle Publishing will soon have a new format: goodbye MOBI, and hello to Kindle Format 8 (KF8).
KF8 enables publishers to create great-looking books in categories that require rich formatting and design such as children’s picture books, comics & graphic novels, technical & engineering books and cookbooks.
Updates to Kindle Gen and Kindle Previewer are coming soon — exciting. :-)
And no, you won’t need to provide two formats. Amazon handles it all. See the Q and A on the above announcement page.