Spotify connect volume control broken since ios 17.4 update

same here with my iPhone 15 pro. Restarting my phone temporarily fixes the issue but I’ve resorted to using airplay instead of the direct to Sonos connection.

Sonos Spotify connect devices are no longer able to adjust volume with volume buttons in the Spotify app after upgrading to iOS 17.5.1. The volume in the Sonos app still works and when using airplay they also works.

I have tested it with 3 phones and this fully updated Sonos setup

1) 2xSonos Move (stereo pair)

2) Arc, Sub3, 2xOne SL.

On both Sonos systems the volume control stopped working in Spotify app after upgrade from iOS 17.4.x to 17.5.x. Sonos App OS is S2 build 80.00.08, Model 48. One/Sub/Move are version 16.2, Arc is 16.1.1

I’ve tested it on these phones:

Does not work on IPhone 15 Pro iOS 17.5.1. Spotify 8.9.40

Works on IPhone 13 Pro iOS 17.4.1. Spotify 8.9.40

Works on IPhone 11 Pro iOS 17.4.1. Spotify 8.9.40

I have the same issue if I connect to the system directly, but if I use AirPlay to connect, it lets me control the volume.

I had the same issue, but now I think it is intentional, let me explain:

I have always used Iphone 12 side buttons to control volume when playing on Sonos 3 Play via Spotify app. But this had its own issues when also browsing in social platfroms like Insta, X, the button didnt know always which media volume to adjust. 
 

iPhone volume buttons no longer do anything for me to control Sonos volume when playing via Spotify. But the manual volume slider showing up in Spotify device selection screen works!

The volume controls on an iOS controller device will work if using AirPlay, as the audio sent to the Sonos speaker, or group, is ‘playing’ through the mobile/player App. 

The Sonos App is not an audio ‘player’, it’s a ‘remote’ and the audio initiated using that App, is sent over wireless direct from the chosen source direct to the speaker, or group. It does not play through the iOS mobile device and so in that situation the mobile device volume controls cannot be used to control the volume.

You can use the Sonos App though, or the hardware buttons on the speakers themselves to adjust volume levels. I tend to change speaker/group volume using a voice assistant, either Alexa, or SVC, in my case.