L2TP IPsec VPN client on Ubuntu Desktop 16.04

Question

I try to setup a vpn client on my ubuntu desktop. I know that some packet are now deprecated and not supported in 16.04. I've tried to run sudo apt-get install strongswan network-manager-strongswan like suggested this link but it doesn't seems to change anything. I only get the PPTP protocol under "new VPN connection"

I manage to get the VPN working for windows, macos and even ios but since the recent release of ubuntu and debian it looks like a real nightmare to configure L2TP/IPsec on those platform

Solution

There seems to be a known issue about this. Error message when starting network manager from Terminal:

$ nm-connection-editor 
** Message: vpn: (strongswan,/etc/NetworkManager/VPN/nm-strongswan-service.name) cannot load legacy-only plugin