Configure VPN for an embedded system which uses Ubuntu 10.04

We have an embedded system which runs the very old Ubuntu 10.04 OS. The system is fine for our purposes, and cannot be upgraded for a few reasons. Security using the old OS is OK because it operates in a controlled and protected environment. We want the default VPN ("deb") client packages installed and running to operate a VPN. So, the main part of the project is (i) finding and loading the historical VPN packages, and (ii) making sure the VPN starts from the command line. The server side will also be an old version of Ubuntu (probably 14.04), with the equivalent historical packages loaded to support the server side of the VPN. The end result of the project is we can simply establish and control the VPN using the command line for both the client and the server.