TARGET DISPLAY MODE IS BACK!! Mac OS Ventura.
Legacy support for Thunderbolt 2 on older Macs OCLP
insane that this still works!!!

Need to be running Open Core Legacy Patcher and Mac OS Ventura or Monterey.
Need a THUNDERBOLT 2 cable

Command F2

Big Thanks to @mrmacintosh and OCLP Team!!
   / @mr.macintosh  

Use an old iMac as a monitor.
iMac 2012 and iMac 2013 running Ventura & Monterey & Open Core Legacy Patcher.

According to Apple these models are supported
https://support.apple.com/en-us/HT204592

• 24-inch and 27-inch iMac models introduced in 2011, 2012, 2013, and mid 2014
• 24-inch and 27-inch iMac models introduced in 2009 and 2010

To use any of these iMac models as an external display:
The iMac used as a display must have macOS High Sierra or earlier installed. (PROVED FALSE BY THIS VIDEO)

The other Mac that you're connecting it to must have been introduced in 2019 or earlier and have macOS Catalina or earlier installed.(ALSO PROVED FALSE BY THIS VIDEO)

The cable connecting the two Mac computers must be a Thunderbolt or Thunderbolt 2 cable.

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Here is what we know so far.

The M1-M2 macs should work with Older model iMac 2009-2010 that use Mini Display Port. (also work with Windows Computers)

The 2011-2014 iMacs work with TDM between only those year models. They will not TDM to the M1-M2. There are OS restrictions APPLE Nerfed TDM feature after High Sierra.

The 2015-2023 iMacs are RIP. Though beautiful displays. They never supported TDM and so we are all left with Airplay 🤮 or a possible Work around using software and a Capture Card
   • MY M1 MAC MINI AND MY 2013 IMAC  

All this provided that the display macs are running OCLP. in some cases the HOST computer may also require OCLP to enable certain features.

I have not attempted a daisy chain but in the past this was an option.

Apple nerfed TDM but THANK YOU TO OCLP to the rescue.