To coincide with the release of Kingdom Hearts 2.5 HD Remix in Japan, the Kingdom Hearts Memorial Ultimania also saw a release. This guide contains content pertaining to every single Kingdom Hearts game that has been made available in addition to some some exclusive interviews and messages. Included among this was a message from series creator, Tetsuya Nomura regarding Kingdom Hearts III.
Thanks to sqex.info for the translation.
Message on KH3 from Tetsuya Nomura