HTTP/2 is the next major iteration of the HTTP protocol and is intended as a replacement for HTTP/1.x. HTTP/2 is designed to improve page-load times over high latency connections, most notably by supporting transaction multiplexing over a single TCP connection.
HTTP/2 is supported in Cloud Load Balancers for client-side requests. This allows HTTP/2 enabled clients making requests to Cloud Load Balancers to take advantage of the performance gains at the load balancer without the need to upgrade the server application.
HTTP/2 is enabled by default for all client connections to HTTP or SSL Terminated load balancers. If a HTTP/2 client connects to a configured load balancer the HTTP/2 data received from a client will be translated to HTTP/1.1 before processing it and forwarding it to the load balancer nodes.
Some browsers do not support HTTP/2 over an unencrypted connection. To maximize the number of users who can access the service using HTTP/2, it is recommended that you enable SSL Termination feature for your load balancer.