The new Mac mini (Late 2014) has no upgradable Memory. Its 4, 8, or 16 GBs of 1600MHz LPDDR3 are soldered to the logic board. A suction cup is required to remove the Bottom Cover. Six T6 security screws are required to remove the Antenna Plate. Each security screw must be replaced before the Mac mini can be reassembled.
This is disappointing, especially as the form factor didn’t change. I would have expected this from a radically different design, but that’s not what we got. The insides may be updated (like that PCIe SSD), but the shell of the Mac mini only changed to make it more difficult to work on.
Of course, the original Mac mini required some knowledge (and bravery) to open. The machine that was just replaced was easier to open, but while RAM was trivial to access, the hard drive was a little harder. This new guy seems to be more locked-down than ever before, and on a cheap machine, that’s frustrating. If someone buys that $499 model, being stuck with 4 GB of RAM forever feels almost punitive.