I wish I had never downloaded the “new” app. I got migrated without my consent. Several longstanding automations do not work. I can not revise them without getting the Network Error. Newly created automations do not work. This is insane and a real good reason never to buy anything Samsung ever again.
Unfortunately, once the migration runs… it can’t be reversed. Not sure how it migrated without your consent as I thought it required you to click on the banner. Are you certain you were migrated? Is there a banner in the Classic app informing you that this location has migrated to the new SmartThings app?
As for the longstanding automations… do you mean Routines? If so, once migration runs, routines can no longer be edited or created in the Classic app.
If you have issues with automations in the new app, you can ask questions on the forum as there are many users who enjoy assisting others. Or at least we will try
Hang in there.
Also, feel free tO contact ST support for help or post comments on the migration.
If you were migrated, you cannot reverse the migration (SHM and Routines are permanently gone). You need the new app to modify Automations or STHM. However, you can go back to the Classic app and use it for device control… at least until next month when they turn it off.