HTTP/2 protocol error and no faster performance

I have found problems with HTTP/2. This just a bottle to the ocean in case other people noticed the same thing. Using curl -I and typing a url that should return a 404, I received the message: curl: (92) HTTP/2 stream 1 was not closed cleanly: PROTOCOL_ERROR (err 1) I curl from my macbook and i know my curl works well with http/2 because i have tested curl against cloudflare.com I tried to rebuild the HTTPD conf, I changed the global Apache config. to default but it didn't change anything so that I had to deactivate HTTP/2 to get a normal 404 error when I use a curl -I against a missing page. The existing pages work fine. I have already seen the following: GET / HTTP/1.1 Host: server.example.com Connection: Upgrade Upgrade: h2c And server return 200 OK if didn't support HTTP/2. If support it then server returns: HTTP/1.1 101 Switching Protocols Connection: Upgrade Upgrade: h2c [ HTTP/2 connection ... ] If you only look at the HTTP headers of the first bot request (example: google bot requests), this does not provide enough information about whether it accepts HTTP/2 because there is an upgrade process before exchanging data. The HTTP/2 implementation looks much more complicated than marketed. I think it may have unexpected consequences for web servers. Is it worth taking a risk on production servers? This was an old website on my cpanel installation. Strangely enough, I curled a missing page on a website that I have created in October 2017 in Cpanel and everything worked fine. Also strangely enough, I have used pingdom to test a website with HTTP/2 and HTTP 1.1, and the pageload (using php 7 and wordpress) was always faster using HTTP 1.1