Proxy Protocol implementation never uses http2 (nginx)
Enabling the proxy protocol disables http/2 mode
Proxy Protocol should also serve the website as http/2 instead of http/1.1
ISPConfig version: 3.2.2
This might affect Apache as well. But I haven't checked, as we have not Apache running.
Patch attached Allow_proxy_protocol_to_use_http2_instead_of_http1_1.patch