Incompatible Software Error 9 Trying to downgrade back to S1

  • 21 February 2021
  • 2 replies

So my daughter installed the Windows S2 app on her laptop and it prompted her to upgrade - being an impatient teenager, she clicked yes and now I have an unintentional mixed systems, but the S2 upgraded units won’t downgrade in the S1 app on my iPhone or Windows machine - I’m getting Error 9 and the help page for this is completely useless.  It says try again or run a split sytem.  Try again doesn’t work and I don’t want a split system. On top of this, it’s not even clear why the app just let her initiate this partial upgrade without some serious warnings or didn’t ask for the primary user password. I don’t want a split system so how do I get these upgraded units to downgrade back to S1 without an error? 

2 replies

Userlevel 5
Badge +16

Hi @cptndave

Welcome to the Sonos Community and thanks for bringing your concern to our attention. Let me share some information with you.

Error 9 occurs when there is an issue with downgrading your Sonos system firmware. This can happen when the Sonos S1 Controller app tries to perform an update while the Sonos system contains a mix of products running S1 and S2 software.

It is possible to run your Sonos on an older software version (S1 system) and older app (S1 app). If you are currently running S1 and S2 systems, and you want them combined in the S1 system, you need to downgrade your S2 system back to S1. To do this, you need to factory reset the speakers upgraded to the S2 system and add them to your S1 system using the S1 app.

Note: You can downgrade your Sonos products to S1 if you have at least one Sonos product running in the S1 system. 

Let us know how you get on with the advice above. In case you run into any issue during the setup, please reach out to your support team to help you out.  If you have any further questions or concerns, we'll be glad to assist you.

So is the best way to do this to unplug all upgraded S2 units and then bring them back into the S1 system one by one by factory resetting each one and then downgrading it to the S1 system such that there are never any active S2 devices?  Is it possible that they can be downgraded without the factory reset if they are the only S2 unit powered on?  I guess it is easiest enough to try this before resetting.