Asset Optimization on HTTP/2

Hi,

Hummingbird Pro is currently installed in our site as to replace WP Rocket. I'm trying to setup Asset Optimization. When I visit the page, it says our site is on HTTP/2.

Does it work on HTTP/2 sites? I enabled the combine option on css files but doesn't seem to work.

When we use WP Rocket, minify and combine seems to work fine on our site.

Thanks