There's a merged pull request on the void-packages repository

riot-desktop: update to v1.5.15
https://github.com/void-linux/void-packages/pull/21023

Description:
I'm no longer using Void Linux but was approached via Email to upgrade the package, so here it is. I'm marking this as orphaned since I don't plan to update this in the future.
Tested it in a xfce vm and even tray icon worked fine.