In a recent engadget article, Jon Fingas points out the following:
If you're planning to snag the new Mac mini and load it up with aftermarket memory, you may want to reconsider your strategy. Macminicolo owner Brian Stucki (among others) has discovered that the RAM in Apple's latest tiny desktop isn't upgradable, much as you'd expect with the company's laptops and the 21-inch iMac.
(Score: 3, Interesting) by tonyPick on Monday October 20 2014, @08:39AM
If all the RAM was soldered on the motherboard then you cant upgrade it (without hardware modifications)
According to this it is Soldered;
http://www.macrumors.com/2014/10/17/mac-mini-soldered-ram/ [macrumors.com]
http://blog.macminicolo.net/post/100240431773/a-look-at-the-2014-mac-mini [macminicolo.net]
So do you have a citation for the "Not Soldered, just custom" version of this story?