@TB1407 

FYI, all the TP-Link powerline adapters are compatible with each other. 

While cause the current adapter is 4020P, if you want to add another single powerline extender unit with wifi function, the TL-WPA4220, TL-WPA4530 are good choices; 

Note: The model begins with TL-WPAxx means that this unit supports wifi function.

You can read case 1 of the below statement.

https://community.tp-link.com/en/home/stories/detail/564

May it help.

Good day.