I purchased Decor8 only for the feature which lets you change the tile colors, or at least the standard tile colors. It didn't say anything on your website about this function being exempt from running on Win 8.1. It did however say that customizing rows and such wouldn't work.
Now, I bought Decor8 after reading this little review on ProgrammerFish.com. It said that your new update made it possible to change the tile color - even on Win 8.1! Of course, this could have been several versions back for all I know, but I hope this is not true.
I didn't spend serious money on your software, so I won't bother asking for a refund. I'm actually happy that your software is so affordable! I do hope, however, that you'll be able to fix this in the future.
It would also be nice if Decor8 could change the color of 3rd party app tiles as well - I get the impression that it doesn't do that now. I understand if this can't be done, of course.
That's basically all I wanted to say. Otherwise I think your program is awesome, so keep up the good work!