purger directive not available

[Dewangga Bachrul Alam]

Hello!

I am using nginx 1.8.0 on Cent OS 7, tried to enable purger directive,
mentioned on
http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache_path

But got error like this :
nginx[46931]: nginx: [emerg] invalid parameter "purge=on" in
/etc/nginx/conf.d/proxy.conf:5

My complete directive are like this :
proxy_cache_path /var/cache/nginx/proxy_cache levels=1:2
keys_zone=mycache:10m inactive=60m use_temp_path=on purger=on
purger_files=100 max_size=20g;
proxy_temp_path /var/cache/nginx/proxy_temp 1 2;
proxy_cache_key "$scheme$proxy_host$uri$is_args$args";

Any hints ?