actually the LITE includes python 3.5 so I did not need to load it.
Mike the Lite version of any Linux version is exactly that. A stripped down version of the OS and the bare essentials to get your Pi booting to the CLI.
It allows you to select particular packages like Python to install from scratch with all it's relevant dependencies. So many other packages rely on Python to operate and particular versions you will find have a release candidate tied to them. The Desktop version of Raspbian will have many Python reliant packages installed.
To get the latest version of Python from the Raspbian repositories the sudo apt-get update and the sudo apt-get upgrade will achieve this. Bear in mind that the Debian repositories (the repositories where most of the Raspbian packages are extracted from) are usually a number of versions behind.
In order to acquire a later version you need to step outside of the Aptitude package manager and compile and install the latest version from a GitHub. Once you begin doing this you need to know what you are doing as this method will not know or check that you already have an earlier version installed. If a later version of a package is installed on top of an earlier version it usually ends up in a broken OS.
I have mentioned it here many times to go with Raspbian Lite and now you have discovered why. Nothing magic really. Installing Raspbian Lite allows you to construct and tailor your own Raspbian distribution particularly when it comes to using your distribution as a server, as in Domoticz or HomeGenie.
You should never need to use a GUI on a server as all maintenance should be carried out remotely once the initial installation has been completed. Using the Raspbian Lite version alllows you to construct a dedicated server with only the essential packages that relate to that server's operability. Nothing more, nothing less.
Packages that require SSL authentication to install can be resolved by installing the relevant SSL certificates on your system. Whether you use the Lite or the Desktop version is not relevant here.
If you want to tie your system to a particular release of a package it's just a case of issuing a particular command to make the Aptitude manager aware of this.