I'd appreciate any suggestion, I'm trying to use gzip plugin and it does not seem to work, my config is as follow:

gzip.so /etc/trafficserver/gzip.config

/etc/trafficserver/gzip.config :
# Set some global options first
cache true
enabled true
remove-accept-encoding true
compressible-content-type application/json
flush true[

After that I restart ATS, see in logs:
 NOTE: loading plugin '/usr/lib64/trafficserver/plugins/gzip.so'

When I make a request to ATS from firefox:
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:41.0) Gecko/20100101 Firefox/41.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: pl,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Cache-Control: max-age=0
I get these headers in response:
HTTP/1.1 200 OK
Server: ATS/5.3.0
Access-Control-Allow-Origin: *
Expires: Thu, 22 Oct 2015 14:08:29 GMT
Cache-Control: max-age=3600
Content-Type: application/json;charset=UTF-8
Date: Thu, 22 Oct 2015 13:08:29 GMT
Age: 1075
Content-Length: 118
Connection: keep-alive

No gzip Content-Encoding.

What am I missing??