The help docs mention marking for upgrade. The context menu and menu bar do not have this option listed at all, and the only non-greyed-out options are marking for removal or complete removal. There are some 40 packages in "Installed (upgradeable)" but there doesn't seem to be any way of actually upgrading them. This is on Linux Mint 17, 32-bit. What am I doing wrong?
sudo apt install --only-upgrade [packagenames] - seems to solve this issue, from the command-line side.
Anyway, it is really sad seeing Synaptic having removed such really relevant features...