Upgrade xibo 1.7.9 --> 1.8.5 (Centos 7.4.1708)

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Hello
I want to update my xibo in production (1.7.9) to the new version 1.8.5:
operating system: CentOS Linux release 7.4.1708 (Core)
#mysql --version
mysql Ver 15.1 Distributes 5.5.56-MariaDB, for Linux (x86_64) using readline 5.1

] # php --version
PHP 5.6.33 (cli) (built: Jan 3 2018 13:02:21)
Copyright © 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright © 1998-2016 Zend Technologies

I do not know which is the simplest (with or without docker) to update.
What are all the steps to go to make this update. I am novice and I prefer to have step by step to evade any problem on the production server

thank you very much

Upgrading instructions for various installation are linked here - https://xibo.org.uk/manual/en/upgrade.html

Docker would probably be easier going forward, however it is not required, just recommended.