The World Wide Web Consortium (W3C) has declared the HTML 5.1 spec is now a "Recommendation", the body's jargon declaring it is done, dusted, signed off and utterly complete.
The full spec is here for your reading pleasure and the list of new features is here.
Among the more interesting new bits, the <picture> and srcset
attributes will let browsers make dynamic choices about the best image to use depending on screen size and where a picture appears on a page. The <menuitem> and type="context"
may get some nervous as they mean browsers' menus can be changed. ®