Why you should switch to HTTP / 2

HTTP/2 is an internet protocol. It is the next version of HTTP/1.1 

Majority of websites on the internet today use HTTP/1.1. internet protocol

The advantage of using HTTP/2 internet protocol is that, it can considerably improve your website performance (in terms of server response time) and speed. 

HTTP/2 supports Multiplexing (multiple requests in a single TCP connection) which means request for web resources (javascript files, css files, fonts, images etc) can be executed into a single request. This considerably improve website performance and reduce page load time without any code changes.

Though HTTP/2 is designed to work with both HTTP and HTTPS, majority of the web browsers at present, only support it over SSL.

So in order to qualify for using HTTP/2, your website must already be on a secure connection (https).

If you are using cloudflare,  you are most probably already using HTTP/2 . If not then login and enable it.

Source: https://www.cloudflare.com/http2/

Use this tool https://tools.keycdn.com/http2-test to test whether your website supports HTTP/2

If your website does not support HTTP/2, then ask your web host to enable it for you. Majority of web hosts don't support it and if you are on a shared hosting, then you are out of luck, as changes need to be done on the server level. 

Enabling HTTP/2 is quite technical which involves downloading and installing mod_http2. So if you are not a web developer, you may have a hard time setting up HTTP/2 on your web server. 

If you are using a dedicated web server, you can ask your developer to enable support for HTTP/2

I use both dedicated server and cloudflare and i have enabled HTTP/2 both on my CDN and at the server level. So even without using cloudflare, my website can still support HTTP/2.

You won't see any visible difference once you switch to HTTP/2. Your website address will remain the same and there will be no changes to the way your website looks and behave. The server response code returned by your web server will stay the same.

For example, if your server returns 200 OK for a particular page, it will continue to return the same status code after switching to HTTP/2

I have been monitoring the use of HTTP/2 on other websites for months and still haven't see any side effects like web browsers throwing error, negative effect on search engine rankings etc. 

However what you will notice is improvement in website speed.  Your website will seem to load faster.