As of Dec 6th, 2016 WordPress 4.7 “Vaughan” is available and in following with WordPress tradition is named for a jazz musician. In this case the team chose vocalist Sarah “Sassy” Vaughan:
There is a video introducing the Update made by the WordPress team as well:
Should you update an existing website to WordPress 4.7?
You will probably want to make this update as it is a pretty major one with a lot of cool features including updates to the REST API content endpoints, Custom CSS, user Admin languages, PDF Thumbnails, changes to the editor, starter content for new sites, and more. You can read more here and here.
As with any WordPress core files update you should be testing your theme on a separate server before going live, if you have customized your theme files. There are a lot of things that change under the hood with these and they can play havoc with layouts and other functions.
Word of Warning on Video Headers!
One of the new features in WP 4.7 is the ability to add video clips to your websites header/top of the page. This is the latest thing for all the cool kids. Please please please use this carefully. Video files are huge and will make your site take longer to load especially for anyone on their cell phone. Yes this looks cool but not if it can’t load or eats up their pricey cell phone bandwidth. If you decide that a video header will be helpful to your users then try to get the file to be under 1MB, please.
The cool thing is that the WordPress team took a lot of things into consideration when implementing this. For small screens the video header does not show up by default so mobile users shouldn’t be as affected. It is also only available on the front page by default. They also suggest you have an image matched with the video so that while the video downloads there is something displayed.
If you want to use video headers please read this page.
Go get WordPress 4.7 and see whats new.