Sonos release 4 August 2024 (I'm guessing the date; I updated these on Tue 6 August):

There is a fault with the Android & iOS controllers: neither display the section called "Your Sources", which, in my case consists of [1] Music Library and [2] Line-In [Amp]

The Music Library is accessible (it resides on a powered-on Windows device) and (of course) I am able to see all of its contents on the Windows version of the controller.

But when I start the Android controller and the iOS controller, neither controller shows "Your Sources". Note that the Windows device was already up and running and playing (using the Music Library) to a Roam speaker with no issue.

I then power on both Sonos Play speakers (and the Line-In Amp) .. and magically.. the Android and iOS show up the "Your Sources" details.

What could possibly have prevented seeing my sources on those two mobile versions?? I can’t believe the mobile versions are closely-coupled to the Play speakers to trigger “seeing” the music library.

Thoughts, advice and sympathy welcome.