The app has not been touched in 3 years and is, now, displaying bugs.
The app was last updated on November 5 , 2018. I have have used the app and it's features extensively on a wide variety of devices from very old, very new, cheap and expensive. I haven't run into any major operational bugs with it.
Now if you want to talk about an outdated app with bugs (and no android support) one needs to look no further than iCab...
The DCS Explorer it extremely forgiving on power input options. It doesn't matter if you choose AC or DC, keep the volts below 24, and the internal current protection + the 5 amp fuse will make sure your 1000 watt power source won't weld your trains to the track.
Best option for the explorer is an old laptop power supply with the 2.1x5.5 barrel plug. most are around the 19 volt & 4.75 amp range which will give you about 90 watts of power. The internet is littered with these things and they make an excellent power source for around $10.