After updating to QGIS 2.18.5 using ubuntugis ppa my QGIS 2.18.4 installation was removed and I get an error about unmet dependencies when I try to install QGIS at the terminal:
The following packages have unmet dependencies: python-qgis : Depends: python-future but it is not installable E: Unable to correct problems, you have held broken packages.
I have seen similar posts like this and this on SE, but they were not able to resolve my issue. I have python-future installed in python 2.7, but I still cannot install QGIS. How might I resolve this problem? I have also tried installing the LTR, but this results in an even longer list of unmet dependencies. My OS is Linux Mint 17.3 (Ubuntu 14.04).