Does Big Sur break Target Display mode from 2015 5KiMac to a 2009 iMac?

[arbitrage]

I have been reading up on people not being able to use TDM anymore on Big Sur with M1 macs. There was discussion that Big Sur eliminated TDM for good. But then other reports seemed to say that the iMacs without TB ports could still be used (like my 27" 2009 iMac).

I currently run my 2009 27" iMac (on El Capitan) in TDM from my late-2015 5KiMac (on High Sierra). I want to upgrade to Big Sur on the 5KiMac but don't want to break TDM to my 2009.

Can anyone confirm that it still works this way.

 

[arbitrage]

Anyone?

 

[CWallace]

Per reddit TDM was deprecated with macOS 11.

 

[davetroup]

Just saw this. If I understand correctly, TDM goes away if you install Big Sur on the "display" Mac.

I am running two iMacs, one is a newer (2019) iMac running Big Sur (11.2.3) and the display-only iMac is an older one (2011?) running an older pre-Big Sur OS. TDM still works for me fine. Again, the TDM Mac is only used as a display so I have no need to update its OS.

But I think if I DID update the TDM Mac to Big Sur, I'd lose the ability to use it as a display to my newer Mac.

Hope this helps.