If you've ever wanted to use an old Mac as a dumb display for your new MacBook, AirPlay Display is for you.
AirPlay iPhone to Mac (NEW feature)
Target display mode used to let you repurpose an iMac as an external display for another Mac. That feature is gone, and only works on older machines, but Apple has resurrected the concept with AirPlay Display. With AirPlay Display, you can use any nearby Mac or iPad screen as a secondary or primary display. It’s both surprisingly useful and a little frustrating.
“Target Display Mode was a system feature in macOS that allowed one iMac to act as a display for another Mac. It still works with Thunderbolt on pre-retina iMacs,” Jonathan Tian, co-founder of smartphone data transfer service Mobitrix, told Lifewire via email.
AirPlay Display is like magic. You open the display preferences on your Mac, just as you would if you were connected to a regular external monitor. At the bottom left of the window is a dropdown menu for “Add Display.” Click that to bring up a list of available Macs and iPads.