Xenforo Possible the fast_cgi cache on xenforo 2.1.x ?

Not sure, but you can take a look at this implementation
https://community.centminmod.com/th..._cgi-cache-on-xenforo-2-1-x.19103/#post-81321

Cache selected URI only.

 

Untested but should work.

Code:

### Start FastCGI Cache
map $http_cookie $nocachecookie {
    default                    0;
    ~xf_user                   1;
    ~xf_style_id               1;
    ~xf_session_admin          1;
    ~xf_lscxf_logged_in        1;
}
map $request_uri $nocacheuri {
    default                 1;
    ~^/threads/             0;
    ~^/posts/               0;
    ~^/forums/              0;
    ~^/categories/          0;
    ~^/members/             0;
    ~^/pages/               0;
    ~^/attachments/         0;
    ~^/css.php              0;
    ~^/proxy.php            0;
    ~^/$                    0;
}
fastcgi_cache_path /var/run/nginx_fastcgi_cache levels=1:2 keys_zone=fastcgicache:512m inactive=30m;
### End FastCGI Cache