Can't upgrade to 2.1.2

[gabwik]

The web setup Wizard is not working, Welcome to Magento Admin, your online store headquarters.
To use the Magento setup wizard sign into your Admin account and navigate to System => Tools => Web Setup Wizard.

And when I try to upgrade trough composer I got 

The "https://repo.magento.com/packages.json" file could not be downloaded ( 

  HTTP/1.1 500 Internal Server Error)

what to do?

[Cosnett]

Authorization needed to see it. You can download magento 2.1.2, data migration tool and code migration toolkit at http://devdocs.magento.com/guides/v2.1/release-notes/ReleaseNotes2.1.2CE.html

[gabwik]

I decided to use 1.9.x instead. There is too many things that still not working as you could expect in Magento 2.1.x. 

[Cosnett]

It can be a good choice. I think v1.9.2.4 is a stable version for user.