Great! Which is it?

That’s my question? Or should I look at upgrading to arc to be more compatible with newer tvs?

If your TV is old and your Playbar is still okay x and you do not need Dolby Atmos -  I would not change soundbars. The Play 1’s and Play 3’s on your profile also cannot be used as surround with the Arc Ultra. I’d go for a new TV first, just make sure it’s got an optical out.

I have a 10 year old Samsung tv I want to get an 77” oled, my soundbar is paired with surrounds via sonos amp. Was thinking new tvs might not connect to old soundbar?

The ply ones and threes are in other rooms not connected to theatre

As suggested, if it has an optical out, it should connect just fine. It may be a challenge, though, finding one of that size and new that does. 

I have decided to also replace playbar with arc ultra. So final setup new lg c4, arc ultra, sonos amp to in ceiling surrounds, and original Sonos sub. I was able to configure original system myself. Is the new setup any more complicated?
 

Nope. These are the steps I would follow:

• unbind/remove the sub and amp from the home theatre room.
• factory reset the playbar if you play on selling it or giving it away
• setup the Arc Ultra
• bind the sub and amp to the home theatre.
• trueplay tune your new setup.

Thanks

Danny, are you saying that the Gen 2 Amp and Gen 1 Sub will work with the Arc Ultra once bound?  That’s fantastic but I didn’t think the new Arc worked with older equipment. 

Also, can you please detail or link how to do the binding part of your instructions?  thanks!! 

See 

All generations of Subs can work with the Ultra.