It's the first time that this happens, I've updated many times without issues, but it seems that the latest changes are introducing some new "features" that are breaking my site.
I'm using a deeply customized theme, and after the updates, the content is still presents, but the layout is no more. It seems that the theme is not applied anymore.
However I was able to restore the site from a previous backup, and now I'm leaving it as it is.
My site is hosted on some provider's Apache server, inside a folder, and I've set some rules on the htaccess to redirect the traffic to it. Until now it's always worked.
I have an exact copy of the same site on a server of mine, running Nginx, and there the update does not break the site.
Perhaps the URI changes introduced with the new update?
Any ideas?