Yours nginx configure - old version

if (!-f $request_filename){
    set $rule_0 1$rule_0;
}
if (!-d $request_filename){
    set $rule_0 2$rule_0;
}
if ($rule_0 = "21"){
    rewrite ^/([\w+-]\+?)/?$ /yourls-loader.php?id=$1 last;
}