I have an Early 2009 Mac mini running 10.9.5. It runs Indigo, WeatherSnoop, Airfoil and Homebridge without a problem.
I bought a used 2011 mini hooked to my tv that does iTunes, Plex and serves media around the house. My workhorse computer is a 2016 mini with an i7 and SSD. It is more than enough horsepower for everyday computing.
When I buy a new computer, the others are like hand me downs to the other tasks.
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