HTTP/2 (originally named HTTP/2.0) is a major revision of the HTTP network protocol used by the World Wide Web. It was derived from the earlier experimental SPDY protocol, originally developed by Google. HTTP/2 was developed by the Hypertext Transfer Protocol working group httpbis (where bis means "second") of the Internet Engineering Task Force. HTTP/2 is the first new version of HTTP since HTTP 1.1, which was standardized in RFC 2068 in 1997. The Working Group presented HTTP/2 to IESG for consideration as a Proposed Standard in December 2014, and IESG approved it to publish as Proposed Standard on February 17, 2015. The HTTP/2 specification was published as RFC 7540 in May 2015.
The standardization effort was supported by Chrome, Opera, Firefox, Internet Explorer 11, Safari, Amazon Silk, and Edge browsers. Most major browsers had added HTTP/2 support by the end of 2015.
According to W3Techs, as of November 2018, 31.8% of the top 10 million websites supported HTTP/2.
So one of my customers is creating a calling card service to call abroad. Without entering in many details, the big challenge here is setting a variable after leg B has been answered. It took me a while to figure out how; I can tell you now that exporting variables locally or non-locally (nolocal:) doesn't work. But then, I found the right way.
For some quite years I have been managing WEB servers for hosting with the command line. It was driving me crazy, but I haven't found yet a friendly solution. Later, in one of my past jobs, I was introduced to cPanel. It was not a good experience. I can tell that cPanel, first it is not free, it has an easy installer but the way it is though it is not the best for a Linux guy. cPanel (when I tested) bundles its own Apache and other software, so security fixes rely on cPanel guys, not on your distro updates. cPanel web interface is awful, too many ports opened! To find a single option you need to go into many menus as possible.
After a while, I discovered ISPConfig and while testing I started liking it. It uses system RPM's, it can run on a VPS or bare metal box and configurations are very easy to follow. As any management software, installing is not a short or easy task. You can look and you will find long documents on how to configure ISPConfig, you may need to download some source tarballs and compile manually; in order to make this easier for everyone, I have developed these RPMs for Centos 6 and 7, and I have published them for your happiness in the OKay repository. Please read my short guide on how to configure it fast.
And yes, It works in CentOS 6 and 7. Some people still use CentOS 6 for an unknown reason.
Following my guide, you can install ISPConfig in 5 minutes.