I'm following the guide located here:
https://github.com/Plailect/Guide/wiki/Part-5-(arm9loaderhax-&-AuReiNAND)
After downloading the latest release for Aureinand, I changed my folder name from "rei" to "aurei", copied over the contents of my "rei" folder to the "arei" folder, replaced Aureinand.dat and arm9loaderhax.bin with the new files from the new version, and replaced my original default.bin file with the new Decrypt9.bin file, changing its name to default.bin and placing it inside my payloads folder. Oh, I also lower-cased all of my folders too, just to make sure that wasn't the problem. After all of that, Decrypt9 doesn't boot when pressing L+R. I don't know. Maybe it'll start magically working on a later version.