Apple in macOS Catalina introduced a new feature called Sidecar, which is designed to turn an iPad into a second display for a Mac, either extending what's on the screen or mirroring the content.
Apple hasn't yet provided details on which devices will work with Sidecar, but developer Steve Troughton-Smith was able to find some details by digging into macOS Catalina's code.
As it turns out, Sidecar is limited to many of Apple's newer Macs, and the devices listed below will be able to use it.
[*]Late 2015 27" iMac or newer
[*]2017 iMac Pro
[*]Mid 2016 MacBook Pro or newer
[*]Late 2018 Mac mini or newer
[*]Late 2018 MacBook Air or newer
[*]Early 2016 MacBook or newer
[*]2019 Mac Pro
It's not clear if this is a complete list, but Troughton-Smith says a long list of older machines are blacklisted from taking advantage of the feature. Some older Macs that are not greenlit for Sidecar can still use the feature via the Terminal command provided by Troughton-Smith, but there's no complete list on exactly which older Macs the Terminal command works with.
Sidecar supports iMac 27" (Late 2015) or newer, MacBook Pro (2016) or newer, mac Mini (2018), Mac Pro (2019), MacBook Air (2018) , MacBook (Early 2016 or newer), and blacklists all the devices in the screenshot pic.twitter.com/DHNDyI98WV - Steve Troughton-Smith (@stroughtonsmith) June 5, 2019
There's no word on whether all iPads will work with Sidecar, or if there will be limitations on that end as well. iPadOS, required for Sidecar, runs on The iPad Air 2 and later, the iPad mini 4 and later, the 5th-generation iPad and later, and all iPad Pro models.
The oldest of these iPads, the iPad mini 4 and the iPad Air 2, use A8 and A8X chips respectively, while the newer models all use more powerful chips.
Update: According to a MacRumors reader who has used the feature, Sidecar works well with the iPad Air 2, which means it should also work with all other iPads that are compatible with iOS 13.
Article Link: macOS Catalina's 'Sidecar' Feature for Turning the iPad Into a Second Display Limited to Newer Macs