I received one of the first shipments of the MSHP wireless speakers (M5WL-BC-P). They have been sitting idle for awhile but I finally decided yesterday to update to v2.12.3 and attempt to integrate them into our every day listening environment.
When I initially set up my speakers in 2018 I remember volume control working fine, responsive both through the app or via the buttons on the 4-in-1 transmitter.
I upgraded at some point v2.08 and I noticed that I lost volume control of the speakers. The only exception being when using iTunes to Airplay on my Mac (Mojave). No volume control though through iOS airplay, or through the buttons on the 4-in-1 transmitter.
I was able to successfully upgrade to "Toasted Pinecone", but now I have no control whatsoever of the volume coming out of the speakers. This includes Airplay 1 and 2, as well as just using the analog input to the transmitter. (I'm using recent generation iOS hardware running 13.3.1)
I sometimes get the visual feedback on the http://axiomair-XXXX.local
volume slider that the volume should be changing, but it doesn't affect the speakers.
There are some other quirks and behavioral inconsistencies, but this is what's currently making the speakers unusable. Maybe somehow the speakers need to be reset? It's not ever clear on how to do that.