Concurrent updates to GDAL (to 2.1.3) and QGIS (to 2.18.5) on Linux Mint 18.1 from the Ubuntugis repos breaks QGIS, with a noted dependency for the virtual package gdal-abi-2-1-2 being uninstallable.
The stable Ubuntugis ppa currently supplies GDAL 2.1.0 (gdal-abi-2-1-0) while the Ubuntugis-unstable ppa has been updated to GDAL 2.1.3 (gdal-abi-2-1-3).
Has anyone found a way around this?
QGIS bug report for those interested is here: http://hub.qgis.org/issues/16386
The ticket has been closed as fixed. Everything should be back to normal now.