Using old iMac (OS 10.6.8) as second monitor for 13 in MacBook Pro (OS 10.15.6)
Until recently, I used my old iMac as a second monitor for my 2015 era MacBook Pro by simply connecting the computers with a firewire cable. All I had to do was connect both to the cable. However, I am unable to do this with my new 13 in MacBook Pro (OS 10.15.6). I connected the computers using a Thunderbolt 3 to Thunderbolt 2 adapter (+ same firewire cable previously used with old MacBook) and have tried holding down Command+F2 on the iMac keyboard, but not luck. Suggestions?
MacBook