Because of the design of the ADT Smartthings panel I am not sure how you would make ADT Tools work with Hubitat as it is completely a separate hub. The only way I can see to make the hubit hub work at all with the ADT Sensors and Alarm would be to use something that keeps the hub devices in sync between hubit and Smartthings. To put that simply that means a sensor has to trigger on ADT’s side, then update Smartthings, and then get to Hubitat. I don’t know how reliable that setup would be. I don’t think it is impossible but it may be more headache then it is worth. With that said though this may still break after the legacy IDE is gone. Hubit also comes with its own challenges as I understand it since everything is local. Even if ADT tools was written for hubitat it may not be possible for it to run well on it considering limited resources. This is all speculation though as i don’t have a Hubitat hub
You are not the only one nervous about the departure from the IDE. It is going to have huge impact on custom applications. What very few people think about or understand is that right now Smartthings is doing a huge amount of processing behind the scenes for all of us with the legacy IDE. I can’t express the magnitude of how significant that is. For those of us that are power users that use programs that are outside of what Smarthings does by default it is a blessing right to help us expand our potential ideas for usage. It really stinks for Smartthings though as i suspect there are several ways the code could be optimized and isn’t and i is just free money and resources to us users that are basically a flat cost to get into the system.
The new system is really to get them out of the processing back end except for explicitly what they want to support. What they did do for advanced users was create a mechanism for folks to effectively create their own backend servers and host their own applications. This means we take o the cost and responsibility of taking care of said applications and underlying infrastructure.
I actually looked into this over a year ago. I even had a test app(not adt tools) working with the new platform and API’s. It is very robust and essentially turns the Smartthings backend into a place to spit events out to remote servers. At this point i don’t have any expectation to support ADT Tools in that kind of infrastructure. First i don’t know what everyone has in their homes and i don’t have any desire to host what some would consider critcal infrastructure for their security. I could certainly do it. I actually already run a 24/7 server and run a vm I could drop such a application on in moments. I just don’t see it being practical.
There is also the fact that right now we don’t know if the ADT Smartthings Panel will even be supported once they go through the final phase and remove old hubs. It may be a completely dead idea if they just stop working it.
If this ever changes though I will let the folks here now, but it seems very unlikely