There are many similar questions on this site, still it is not clear to me which answer to these questions applies to my situation, so please forgive me for asking again.
After updating my software with the software updater I get the following message:
Today I pressed 'upgrade' (because I wanted to upgrade) and I was asked for my password (I wanted to screenshot this window also, but it seems impossible). After filling out my password and clicking 'authencicate' nothing happens.
Just nothing. The software updater is closed and ubuntu pretends nothing ever happens.
Following some internet sources I then tried to do it through the terminal:
sudo apt-get update && sudo apt-get dist-upgrade
It produces an enormous amount of text (which I can paste here if it is useful), but the bottom line is not very reassuring:
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
I tried do-release-upgrade
it answers:
Checking for a new Ubuntu release
Please install all available updates for your release before upgrading.
I have no idea how to do that. Put better: I thought I already did that. See the screenshot above: the software on this computer is up to date. What more can I do to 'install all available updates'?