Can't install Oxidize, please help

Hello,
I’ve followed this https://github.com/ytti/oxidized#centos-oracle-linux-red-hat-linux

But I get the error where net-ssh needs Ruby version >= 2.2.6
gem install oxidized
Fetching: asetus-0.3.0.gem (100%)
Successfully installed asetus-0.3.0
Fetching: net-ssh-5.2.0.gem (100%)
ERROR: Error installing oxidized:
net-ssh requires Ruby version >= 2.2.6.

Can someone explain how how I check the version installed and how I upgrade it?

Thanks

Install ruby 2.3 from scl, that is the default way to do it in centos.

I used this, is this not right:

yum install centos-release-scl
yum install rh-ruby23 rh-ruby23-ruby-devel
scl enable rh-ruby23 bash

Correct, if you run ruby --version do you see 2.3? Also as the oxidixed user?

Btw this is how my systemd service definition looks like:
ExecStart=/bin/scl enable rh-ruby23 /opt/rh/rh-ruby23/root/usr/local/bin/oxidized