HTTP/2 is the next generation of the HTTP protocol that dominates and continues to define the modern web. On February 18, Mark Nottingham, chair of the IETF HTTP Working Group, declared that HTTP/2 is done.
That doesn’t mean that HTTP/2 is a finalized standard, but rather that the elements that make up the specification have been finalized and the proposed standard can move on to become a bona fide IETF RFC.
But declaring a protocol a standard doesn’t exactly mean that it magically just starts to work. HTTP/2 will need to be supported in browsers as well as the web servers that deliver web traffic to those browsers. That’s where Nginx fits into the equation.