It usually takes a little while for the software companies to catch up with new(-ish) models. You can bet that they're working on the KP... they want as many people buying their software as possible
I can't speak for DxO, but AfterShot (and the Pro version) is very poorly coded when it comes to processing RAW images from cameras it doesn't recognise. It won't load my Hasselblad HV files, even though it's just a Sony A99 in different clothes with a different make and model in the EXIF. That's clearly what they test for when importing files, as it just won't accept my HV's .ARW files, even though Sony's own Image Data Converter - and Lightroom 6 stand-alone - load and process them without any problem. It's one of the reasons I'm staying with Lightroom for now...
As others have said, I'd try RawTherapee for the time being. Or, even Pentax's own software... Once you get used to it, it's not so bad, and you can always save the files as .TIF then load them into Dxo or AfterShot for the rest of your processing