Device sidechain/menu broken after Max update to 8.6

Hello everyone - I've recently noticed that one of my favorite devices, the classic M4L envelope follower augmented with side-chain functions, no longer works after the Max update to 8.6; the menu to choose the side-chain inputs has "disappeared" and is no longer accessible.

The Max console reports the following: live.object: doesn't understand "dictionary"

The device is available here: http://maxforlive.com/library/device/4521/ext-in-envelope-follower

I reached out to the dev, Dillon Bastan, but he said that he no longer maintains the device and would be unlikely to find the time to update it.
Unfortunately, I am a complete Max novice and haven't been able to figure out how to fix the error.
Attached is a screenshot documenting the error, the UI of the device, and the live.object generating the error message in the bottom right.

I'm extremely grateful for any assistance :)