Can you post a link, please? There’s been zero indication of such in these forums, or to my knowledge, an announcement from Sonos, which makes this likely just an internet rumor, with no veracity. 

Comment #1146 https://www.avsforum.com/threads/sonos-introduces-arc-soundbar-with-dolby-atmos.3142634/post-62925858

Anybody who knows wouldn’t be posting it in a public forum, so that‘s a rumor at best.  

Agreed. This seems like someone trying to sound important, without having any facts. 
 

Thanks for the link!

The post says “Requires an NDA”. I think we will not hear very much more.

That same user has been asking about the best soundbar to buy in the same forum - I suspect they have honed in on the Sonos Arc and now just trying to discover if there is a newer model in the pipeline before making their decision to buy. So I suspect it’s fake news too.

All closed Sonos betas require an NDA, so that tells us nothing about what is being tested at any one time.

Guess the consensus here is a big “no” but in all honesty (only personal opinion) the Arc is about 3 years old so I wouldn't be too surprised to see something newer in a year or so.

There is a Beta recruitment link on the main site. It’s been there for years and is not model specific.

Here's the only new news and it doesn't suggest a new Arc is forthcoming anytime soon

 https://www.theverge.com/2023/11/15/23962936/sonos-major-new-product-coming-2024-tease

I’d be really surprised if the Arc comes before other, older speakers.