On 19.3: apt-get upgrade safe? universe-repo as well?

Hi everyone,
I am sorry for my basic questions but I hope to contribute in a way that will be helpful for others in the end too at least.
This is a very nice webpage:
http://elinux.org/Jetson_TK1
And I learned some things there.

I was wondering if a step like this:
‘sudo apt-add-repository universe’

And ‘apt-get upgrade’ in general is recommended and considered ‘safe’?
Am I (at some point) likely to kill my Nvidia-GPU-driver compability with Xorg or such?

Thanks for advice/experience/hints,
Martin

I would recommend Updating the Ubuntu 14.04 distribution via
sudo apt-get update
sudo apt-get upgrade
it did not break my rootfs yet,
but it is needed to be careful with X-Server packages and
driver packages which could overwrite Nvidia packages and drivers.
-adding the universe repo does not cause any problems

http://bitkistl.blogspot.co.at/2014/03/evaluating-jetson-tk1-board.html

Best Regards,
Peter Bauer

After you have installed or upgraded any packages, and wish to check if it interfered with nVidia’s extra files, run:
sha1sum -c /etc/nv_tegra_release

This does not include everything, e.g., the module directory has nVidia’s “extra” subdirectory, but I think the checksums cover the normal library type files.