HTTP/2 is a major revision of Http network protocol used by WWW (World Wide Web). It was derived from SPDY protocol (developed by Google). HTTP/2 is supported by almost all modern browsers.

cPanel has recently added support for HTTP/2 in EasyApache 4. Now, Cpanel users can enable HTTP/2 on their server. HTTP/2 can boost website speed loading and there are other advantages as well.

There is underlying issue with release of Apache 2.4.27. Prefork is not compatible with HTTP/2 with this Apache and you may face issue while using HTTP/2 with prefork. There is ongoing discussion on this in cPanel official forum. For more information, you can refer the following thread:

https://forums.cpanel.net/threads/prefork-and-http2.605799/