What is HTTP/2 ?

HTTP/2 modifies how the data is formatted (framed) and transported between the client and server, both of which manage the entire process, and hides all the complexity from our applications within the new framing layer.
The primary goal of modifying the existing HTTP/1.1 to HTTP/2 was to simplify it, increase performance and to improve robustness. And HTTP/2 does all of these marvelously.

HTTP/2 enables a much efficient use of network resources and a reduced perception of latency by introducing header field compression and allowing multiple concurrent exchanges on the same connection. Specifically, it allows interleaving of request and response messages on the same connection and uses an efficient coding for HTTP header fields. It also allows prioritization of requests, letting more important requests complete more quickly, further improving performance.

Earlier iterations of the HTTP protocol were capable of transmitting only one stream at a time along with some time delay between each stream transmission. With the help of HTTP/2, the stream is in a Bi-directional sequence which reduces the delay in communication.

Server Push capability allows the server to send additional cacheable information to the client that isn’t requested but is anticipated in future requests. The client places the pushed resource into its cache for future use. This mechanism saves a request-respond round trip and reduces network latency.