netcat vs nc on CentOS 7

CentOS 7 (and I believe newer versions of Debian) ship with nmap-netcat, which is not the same as the OpenBSD based nc shipped with earlier versions.

The change that affects me immediately is when using nc to connect to a machine via a proxy

Older nc versions ->
ProxyCommand = 'nc -x proxy-server:port %h %p'

Newer nmap-ncat version ->
ProxyCommand = 'nc --proxy proxy-server:port --proxy-type socks4 %h %p'