I wouldn’t expect it to be any different than it is currently. You’d open your controller, use the “add a device” feature, and it would be sure to copy over whichever version of the software that your system is running on.

You won’t be able to add new S2 based devices like the Five or Arc, but you can add items that are for sale now.  

I’m OK with not adding new style products.

I am worried that it will be the same as it is currently… where I’m forced into an upgrade with each addition, and that is going to mean changing  to S2

S1 and S2 are two different systems. You likely will be required to update to the most current version of S1, but you won’t be required to switch over to the S2 system.

I agree with the posters above, but the only possible problem is if Sonos shipped systems with S2 firmware already. While they have to do this for the newest hardware, if they also did this for existing modern products then I don’t believe you could add those to an S1 system.

This is all speculation until Sonos actually ship something though.

Sad conversation with Sonos tech support (waited a long time, but wanted to get it straight from the source.)

The "am I on latest firmware" check is built into the system addition process.  The S1 controller will check for newer firmware when initiating the system addition, which will move it to S2.  And the modern S1 speakers that can take S2 will get the firmware update at the time of the addition.  It doesn't matter what they left the factory with, they move to latest version while being added to a system.

He emphasized that the incompatible systems are only.... the things that early adopters like me bought; and that they will support a split system. 

One of the initial problems Sonos solved for me was the unsynced sound coming from different radios tuned to the same station, which will probably return in a split system. 
My system will have to stop growing.  

@David Somers . I would not regard a response from tech support about this future situation as Sonos' definitive word on this.  The message is, as always, 'wait and see'.

Obviously didn’t hear the conversion you had with tech support, but the above statement doesn’t make any sense to me.  I don’t see how or why an S1 controller would update a device to a version of firmware that doesn’t match it’s own firmware level and that it can’t itself control.  If this were true, every modern speaker would be updated to current S2 when the switch over happens and incapable of being in an S1 system, which Sonos had repeatedly said would not be the case.  I suspect that either the tech was mistaken or there was miscommunication somewhere.

It may be that a speaker that is already at a version higher than S1’s version level, because it was previously in an S2 system, can’t be added to an S1 system...but I highly, highly doubt that.  Most likely, the system will be able to add it, then recognize that it’s not on the version the S1 controller sees as the current correct version, and will update it accordingly.

Danny, perhaps the error is in how I referred to the controller in my post.  I mean to refer to whatever software you’re using.

Since the first (but not last) time I lost the ability to use an old device as a controller, I no longer perform regular system updates until I have no choice.  If you already are on the latest version you may never experience this…. When I add a new speaker, just after selecting “add Product”, I am prompted to update the controller to the latest version.  The options are upgrade or cancel, and if you cancel you exit out of the addition process.  Only after the upgrade completes are you able to begin the addition process, during which it brings the new addition and the existing speakers up to date.

I would love for someone to come along next month and prove that I misunderstood tech support.

My expectation is (and of course this is pure speculation and we will have to wait and see), that S1 and S2 will be totally different systems.

Within a system, you will be able to add new products (possibly from a limited range in S1) if and only if you are on the latest firmware for that system.  The prompt to update to the latest firmware will continue to appear in both systems.  But you will not be bumped up from S1 to S2 because that is a completely different system with different firmware.

The updates in the case of S1 will be just bug fixes and security patches, so controllers are extremely unlikely to go out of date with S1 updates.

On S2, system developments will continue to mean that controller devices and operating systems will eventually become only partially supported and then unsupported, as happens now,

I would nor be surprised if the S2 versioning restarted at 1.0, with S1 continuing from the existing numbering.  I don’t see any reason for any link between the two sets of version numbers.

Of course i could be completely wrong.

My understanding is similar to @John B that the two systems will be different and that if you have chosen to stay entirely in the S1 ecosystem that your components will only ever upgrade to the highest version of that ecosystem, irrespective of whether they are "modern” or "legacy" products. I guess the bigger question is where would you be sourcing these new components from, because after May 2020 any new products will only be S2 compatible? If you are talking about new old stock (NOS), then that will eventually run out. If you meant secondhand equipment when you said “new”, then you will need to be very careful to ask the seller if they moved those components that are today defined as “modern” (for example One, Play:5 Gen 2, PlayBar) from S1 to S2. Of course, you’ll have no problems with “legacy” components (for example the Play:5 Gen 1, and early Connect and Connect: Amp)

I have been understanding of the need to create an S2 but will be far less so if newly manufactured products of the current range cannot connect to an S1 system. I do realise that in due course Sonos will replace all of the current range and then it will be the second hand market only. I do have an expectation that the devices like the One and SL would have a good few years manufacturing  left but maybe I am being foolish.

My assumption is that devices that are both S1 and S2 compatible will be able to move between systems (possibly with a factory reset) at will.  Is that right or is there anything suggesting it will not be the case?

Sonos has never offered the ability to retrograde the OS on a device, and I would be surprised if they do under this new ecosystem construct. I don’t know that they won’t, but I’d be very surprised if a component that was upgraded to S2 would ever be able to go back into service as part of an S1 system.

Yes I'm aware of that but they've never had a scenario where they maintained two sets of software before - with some devices that can operate on either.

Maybe @Ryan A can confirm?

Moving between S1 & S2 at will would proof itself a nightmare for Sonos Support (people getting confused on which fork which device is currently running on, getting stuck during the up-/downgrade process and so on). Most likely a game Sonos isn’t going to play.

Technically going from S1 to S2 is not an upgrade I would suggest - it'sa total change.  So the other way is similar.

Or are people saying that if I choose to keep my Play 5 Gen 2 in an S1 setup, separate to a split S2 setup that I can't move it to the S2 one in the future - or that S1 to S2 is an upgrade and the other way around isn't - even though it's completely different software?

I understand the comments about support but think that's easy for Sonos to ask a customer and would also be included in any diagnostic information anyway.

I think support is not always at the fore of Sonos thinking anyway - especially with regard to having different components and specs for identically names products and even product names themselves..?

That may be what some people are saying, but we are all just guessing.  I share your view (if I understand you correctly) that you can't think of upgrades or downgrades in the context of moving between S1 and S2. 

My hope and best guess is that it will be possible to factory reset speakers that are compatible with both S1 and S2, and add them to whichever system you want them in. They will always have to be added to the latest version of the S1 or S2 software. 

Maybe that is just wishful thinking.....

Yes, you understand me correctly (reading it back isn’t clear as I intended..

My hope too.  I don’t see the issue in resetting and then adding to a ‘new’ system.  If it’s compatible with the System (S1 or S2) it will install the software required for it to run.

Sonos checked back with me to confirm that my support ticket was resolved, so I circled back and got the results attached, which describe a world in which S1 to S2 is separate from the required version upgrades within each system when components are added.
This indicates that there was a misunderstanding on the initial call (perhaps I didn't explain well), or that knowledge of the expected behavior is not yet evenly distributed.  

---- my email to Sonos support:
This topic (adding new components to an old system after the release of S2, without upgrading to S2) has turned into a hot topic on your discussion board…

In my mind, there are/will be three types of components: 
Legacy S1 only (Zone Players, CR200, Bridge, Connect (Gen 1), Connect:Amp (Gen 1), Play:5 (Gen 1))
Current S1/S2 (like Play:5 (Gen 2), Connect (Gen 2), One (Gen 2), One SL, Move)
Future S2 only (like Arc, Five)

I believe I understand the options of keeping an existing system on S1, splitting a system between S1/S2, or upgrading the entire system to S2.

Please confirm my understanding of the following from the phone call:
My experience has been that the “add component” process always includes an upgrade to most current.
After the release of S2, it will no longer be possible to add a newly purchased current S1/S2 component to an S1-only system.

<snip pleasantries and personal info>

----- Sonos support reply:
<snip pleasantries>

For the system, the legacy and current units that you try to add to the S1 system, they will update to the latest version for that system.

However, the future units or the units that already were updating using the S2 system, they can only work using the system S2 because they will be already in a version higher than the S1 system can support.

<snip personal info>
 

As I suspected, a move from S1 to S2 is an upgrade and Sonos will not have a provision for a retrograde.

So after the release of S2, presumably with fairly immediate effect, unless Sonos sells the current array of non-S2-only ‘modern product’ devices with options of either S1 or S2, then:

1. It will be impossible to add a new non-S2-only ‘modern product’ device to an S1 system and
2. It will be impossible to replace any dying/damaged/lost/stolen S1 system ‘modern product’ device

unless one can unearth some old ‘modern product’ stock that was manufactured and sent out before S2 was released, or is found second-hand.  Or they then HAVE to split their system, losing their all-room capability.

Seems people who are forced to maintain S1 systems due to the number/proportion of S1 devices they own will, pretty soon after June 2020, be unable to expand their systems at all, and won’t be able to replace any dead devices either…..without resorting to the second-hand market.

There must be quite a lot of people in this situation who will be hoping that S1 will still be an option to purchase, or regrade to, on non-S2-only devices after June.  Does Sonos intend to accommodate them, or is the S1/S2 differentiation and split capability really just a short-term sop in the march to enforcing uptake of S2 and driving more upgrade-entire-system purchases as soon as possible (albeit without the dire compulsory-bricking-of-replaced-devices policy that had to be rescinded after the outcry) - just not quite as soon as previously intended in the pre-outcry business plan?

Unfortunately, Sonos haven’t chimed in in this thread yet to officially clarify.

@Ryan S can an S1 and S2 compatible speaker be moved from an S2 setup to an S1 setup?

In all likelihood - no. Anyhow, come Monday all questions are going to be answered or at least addressed in some way.

Yes, but the process of how the split happens and what you can or can’t do shouldn’t need to still be unknown now?

How will the split happen - will you install S2 and be asked to make a decision then?  Is S2 getting a last  ‘final’ update (bar thefuture security/patch updates) when S2 is released?

No need to divulge functionality of S2 yet - but it doesn’t seem unreasonable to give users the information of how the biggest update of Sonos software so far will need to be managed by them in advance.  It would at the least allow things to be planned - even potential purchasing decisions.