lein ring server-headless custom-port doesn't works about lein-ring HOT 5 OPEN

This is bug.

If I use this version - all works.
:ring {:handler hashers-example.core/app
:port 6001}
:plugins [[lein-ring "0.8.13"]]

If I use last version of lein ring - doesn't work

Please check

from lein-ring.

I can't reproduce this error. Is it possible that you have a PORT environment variable set? That currently overrides the command line.

from lein-ring.

I use c9.io environment. And with 0.8.13 c9.io works correctly, but with latest version of lein ring doesn't work. MB this is bug with c9 or PORT variable, I don't know.

from lein-ring.

Have you tried changing the PORT variable, or checking its value?

from lein-ring.

printenv command shows:
PORT=8080
IP=0.0.0.0

from lein-ring.