Ubuntu – Update texlive-full 2015 to texlive 2017 in Ubuntu 16.04 LTS

Good morning,
I know that this might sound simple but I would like to avoid any complication since I use TeX daily and I don't want to mess all the things up.
I have installed texlive-full by command line on the terminal, i.e.

sudo apt-get install texlive-full


and I have discovered that the version offered by Ubuntu is from 2015. I have seen that there is a 2017 version of TeX and I would like to install it without problem. Is there a clean way to install over the 2015 version? If not, what are the commands from the terminal to be sure that the previous version is completely purged and then what are the new commands that I have to type in order to install the 2017 version?
Is there a way to add a repository (maybe an official one) in order that any new version is updated automatically without any future worry?

I'm sorry for my poor English, and I hope that this question does not result a repetition, since I would like a kind of guide to install properly the new version of TeX over the previous one, but I have not done anything for now, so I do not want to solve problem in the installation, I would like to know I to make the installation.

sudo add-apt-repository ppa:jonathonf/texlive-2017