I love this program, but I really need to use Decal Layers. Right now the feature isn't available in sprytile, and I see that I have to update in order to get. The thing is, I don't have the option to update Sprytile at all. It's not there in the preferences window. 
I've read that you need to use the blender Addon Updater, which actually involves editing the source code with python. Is this true? I've made an attempt but it was way beyond my ability.

Decal layers is not yet implemented in the Blender 2.8 version. The lastest version for Blender 2.79 has decals though.

Super duper excited to see decals in 2.8.

This tool is a godsend

Ah ok. After reading your comment, I got blender 2.79. But now sprytile seems incompatible with that version of blender. Is there a way to download an older version of sprytile so I can have it work with the old blender?

Ah got it. Thanks a lot, I'm really loving this add on.
I found the older version here
https://github.com/Sprytile/Sprytile/releases/tag/v0.4.50