I use https, want to use HTTP/2, and know my host can do this. I asked them if they could set it up, and they sent this reply that I am a bit confused by. Can someone help me interpret it please?

Before enabling HTTP/2 to your site(s) need to be check by developers, as implementing http2 protocol requires Apache mod_worker or mod_event.

Both requires php-fpm, as mod_php cannot handle threaded php process in parallel and mod_http2 will not work with this configuration. PHP-FPM is installed on your VPS server, however it’s not enabled for your account (website)

Last but not least, you will need to make sure that your site(s) will use correct PHP handler, otherwise all sites after implementing http2, will be broken.

In total it is possible and the modifying the EasyApache4 module process is fast, but it will be time consuming regarding to PHP code checks.

If you have staging site and if staging site can be tested with new configuration before going live with new server settings and software upgraded, I think it will be good start, nevertheless if you want we could execute the changes, but we cannot be responsible if the above checks are not performed and those changes led to your site not to be functional.

I know other hosts, like siteground offer http/2 for wordpress hosting, plus my Stackpath CDN is already serving most of the site over http/2 so I’m guesssing it should be good to go. Do I really need a developer to check all this? Or can I just tell them to turn it on?
Thanks in advance for any help.