If you look around in the forum, you'll find that they hit a few roadblocks with this feature.Not sure what you mean but I was just wondering when the WiiM amp roadmap be updated. It also states, on this forum, that DLNA cast would have been ready by 10/30.
AFAIK this feature has been in the works longer than simultaneous USB & sub output so it probably has priority now.
* hint: starwars