PPTP VPN client for macOS Sierra or iOS 10?

Apple has removed PPTP VPN support in Sierra due to security concerns. See: https://support.apple.com/en-us/HT206844

Unfortunately, I need to connect to an organisation that only supports PPTP (not my decision).

I know about Shimo, but it's $50 and has a lot of features I don't need.

I was hoping to find a free or open source solution? A command-line-only option would be fine for macOS.

I'm even open to more esoteric solutions (e.g. a lightweight linux VM that connects to the VPN, and then shares the connection with host OS, but not sure how feasible this would be or how to do it).

Edit: I see the command-line tool pppd is still present in macOS Sierra, so perhaps it's possible to call this directly?

Edit 2: I tried following this tutorial with an options file from the ArchWiki, and a custom route in /etc/ppp/ip-up, but it gives an error (publish_entry SCDSet() failed: Success!) when I try to run the pppd command, the pppd daemon doesn't seem to be running, and the ppp0 interface isn't showing up in ifconfig. I don't know much about networks and network interfaces, so I'm finding this very confusing! Any help would be much appreciated.

The FlowVPN client is free (and works with any provider).

It supports PPTP and OpenVPN on macOS Sierra and High Sierra:

https://www.flowvpn.com/download-mac/

Just overwrite the FlowVPN server address with any server and it connects.