The online ebook creation tool Pressbooks.com was updated yesterday. I can't see any changes to the admin pages, but the front-end looks a lot different.
Pressbooks is a WordPress-based site that you can use to make Kindle and Epub ebooks (and also PDF), but you can also use it to publish a version of the book online - TOC and all.
That is the part most affected by this change. I haven't used the web publishing option enough to tell you whether it now looks different, but any current Pressbooks user should definitely check on their works just in case.
What do you think of the update?
P.S. Pressbooks is one of the tools listed in my post on ebook creation apps.