HTTP/1 should die; HTTP/2 can do everything HTTP/1 could, only faster

HTTP/2 with WebSockets
HTTP/2 alone makes a huge 62ms difference in the net time to complete the requests, however the browser is still blocked establishing the connection. As WebSockets can now be served over HTTP/2, the requests can also be multiplexed over this connection meaning there is no additional cost to establishing a connection. Figure 3: Timeline for HTTP/2 requests with an existing WebSocket connection.

Source: medium.com