In case you need to open an remote Mongo server to a ssh tunnel.
This covers only the steps for Mongo 3.x, you will need to open ssh for the port as well.
You need to switch between PHP 5.6 and 7.1 on your Ubuntu 16.x, without any docker/vm bs?
Here is one of several ways tpo do it.
Sometimes you can’t just upgrade Ubuntu to >=16 which ships a LAMP with PHP 7 by default .
As a temporary solution you can upgrade your old LAMP to PHP 7 whilst keeping PHP 5.x available.