After almost 20 years since the last release of HTTP, the newest version of HTTP was released in 2015. This new version of the protocol has several enhancements vis-à-vis previous versions. Some of these enhancements also affect the way server applications will be developed.
The first and most important enhancement is that the new protocol will make it possible to send several resources parallel in a single TCP connection. The keep-alive flag was already available to avoid the recreation of the TCP channel, but it does not help when a response is created slowly. In the new protocol, other resources can also be delivered in the same TCP channel, even before a request is fully served. This requires complex package handling in the protocol. This is hidden from the server application programmer as well as the browser programmer. The application server, the servlet container...