The list of releases on this page:
https://www.debian.org/releases/ is out of date.
Its showing 6.0 as obsolete, and the next version as "Buster", to be released on the 17th June 2017. There's no reference to 7.0, 8.0 or 9.0
The date on the page says: "Fri, May 26 23:25:56 UTC 2017"