Apple is the one who made the rules against controlling 3rd party hardware from the hard buttons/lock screen, so why wouldn’t you blame Apple?  Sonos has to follow those rules or the app gets tossed from the app store, nothing Sonos can do about it.  Besides that, you claim you spent money on Sonos, does that mean you get your Apple devices for free?

There are running discussions about this in other threads in this Community. You can follow these discussions (rants). If you want to blame SONOS, the original misstep by SONOS occurred years ago when SONOS developed the lock screen Volume control hack. Yes, it was a very popular hack. Recently, Apple decided to get tough and not allow this sort of hack -- forcing SONOS to remove the hack.

I suggest that you lobby Apple to allow this sort of 3rd party control.

Note that there are a few music service players (Apps) that can play music through SONOS. Because these are iPhone/iPad music player Apps, they can control the SONOS Volume. The SONOS controller is not a music player App, it is simply a remote control for the SONOS system. The SONOS players directly fetch music from the source. Once music play is started, you could actually uninstall the SONOS controller and music will continue. For many of us, this is the main reason we use SONOS.

You must spend you life uninstalling and reinstalling the Sonos app!

I don’t think you understood what @buzz was trying to say. 

I said that “you could actually uninstall the SONOS controller”, I didn’t say that I repeatedly uninstall the controller. (There is no benefit) My point is that the computer/phone/pad can crash, be rebooted, or powered down while the music continues.

It can’t be an Apple issue. I’m controlling volume just fine from my iPhone using standard WiiM Home application. 

Which is a direct player, not a remote control device like Sonos is. 

What is a ‘direct player’?  I can shut down the WiiM Home iOS application or delete it - WiiM mini audio continues playing, just like with my SONOS. 

I have a WiiM as well and it functions the same as  Sonos in regards to volume control in iOS IME. What are you saying is different?

WiiM app Version 2.6.4.23092618

iPhone SE IOS 16.6.

I’m not sure what I’m missing here. 

I use the phone volume up/volume down hardware buttons to control WiiM mini volume no problem 

With my My SONOS IOS application the iPhone volume up/down buttons are no longer functional. 

Yeah same for me except the volume buttons work in Sonos same as WiiM -IOS 17 iPhone 11, Sonos ver 15.8.1

I’m not sure exactly when Apple will absolutely shut down the hack. It’s possible that 3rd party apps will start to crash if they attempt to use the hack beyond some date that Apple has communicated to developers. Rather than having the SONOS controller simply crash after a future Apple update, SONOS may have elected to introduce a controlled feature phase out. This means that some other Apps might be able to continue with their own hack for a while.

What app and what hack are you talking about?

I don't think you understood my sarcasm. Maybe I should have signposted it with a

The lock screen and hard volume button functions on the iOS Sonos app were a hack.  The Sonos app played a silent audio file in the background to fool iOS into seeing the app as a media player, not a controller.  It was then able to hijack the input from those controls to control Sonos devices.  Apple put the kibosh on the hack to enforce their rules about controlling 3rd party hardware.

Sorry, I though you might be willing to learn something new.  Silly me.

SONOS pretended that it was a music playing App and could therefore send Volume commands to SONOS players. Apple has decided that this is a security risk. Any other App that pretends to be a music player will be at risk. I don’t know exactly how actual music players are different from hacks. A Bluetooth or AirPlay 2 transmission will adjust audio sent to the receiver. Bluetooth and AirPlay work with actual music players. A player, such as the SPOTIFY App can send Volume commands to its server and the server can relay the Volume commands to SONOS. This end runs the Apple security risk.

My fault I’m aware of that hack but thought OP was going on about something else.  

That's wrong, e.g. the Harmony app from Logitech is a pure remote control app, it works there too.

Harmony Remotes no longer exist, so Apple’s not going to go after them. 

My hue app seems to be able to control stuff a lot better and thats a remote control.

I have just spent a small fortune moving from an S1 system to S2 and found this. Very frustrating. At least make it easier to get at the volume control or allow preset volumes.

I miss my old CR100 with its big physical buttons. Busy and messy kitchen I want to be able to get at these things quickly, not unlock my phone, find the sonos app, find the room and then mess with some dodgy slider.

Until Apple says Hue can’t do this anymore……..

Could you not use voice commands to turn down the volume on your Sonos devices (your profile does not say what device you use)?

Note that this change does affect both S1 and S2. Since it’s a change being forced by the OS, Sonos has no choice but to alter both controllers. 

Side volume controls still work with YouTube music app and google cromecast speakers

That's because the YouTube music app is a media player, not a remote control.  The difference is easy to see - Start a Playlist on the YouTube music app, then fully exit the app.  The music stops.  Now do the same on Sonos.  The music keeps playing.