First of all, I am well aware of this question: What's the easiest way to upgrade Ghostscript?.
Unfortunately none of the answers worked. I can find
deb files from this list. There, I am surprised to see that the last version of Ghostscript for Ubuntu 14.04 is version 9.10. When I download version 9.15 for Ubuntu 15.04, and I run it (as root), I get the error:
Error: dependency is not satisfiable libgs9
I checked (
apt-get install libgs9) and I have the latest libgs9 installed. Also, this site seems to confirm that last is version 9.10 for 14.04.
Does this mean it is not possible to upgrade Ghostscript?