Trying to install Ntopng 3.2.0 on linux Mint 18.3

I want to use ntopng 3.2.0 ( http://ift.tt/2lrJWsz ) on linux mint 18.3

I can't install the last version found here : http://ift.tt/2amoejh

dpkg: error processing archive apt-ntop.deb (--install): trying to overwrite '/etc/nbox/ntop-apt.key', which is also in package apt-ntop-stable 2.6-899 abort-install Errors were encountered while processing: apt-ntop.deb

the version that works for now is

v.2.3.160415 works well ( installed it like this sudo apt-get install ntopng )

JF

Tks !!