2018 Mac Mini
The Mac Mini is old. The last update was in 2014. Since then, the cheapest Mac has languished with older specs and the same design.
Each year we hope to see a new Mac Mini, and so far it's been a rough several years. There is some hope that 2018 is different.
Apple CEO Tim Cook said the Mac Mini is, "an important part" of the Apple lineup, but so far there is nothing to show for that.
If we get a new Mac Mini expect faster processors, the potential for a new look and USB C with Thunderbolt 3.
This would likely come in a June or September time frame.