If you search the docs, you will find this referenced in the device type section a few times. It doesn’t appear to be supported for SmartApps. ST has recently updated a section focusing on scheduling methods in the docs that does a good job of explaining what is supported for SmartApps. If you let me know what you are trying to do, I might be able to help.
Bump. I also read about these functions in a few of the tutorials, but I haven’t found an API discussing “delayBetween()”. Is this a groovy API? SmartThings? I’ve mostly discovered these functions through tutorials, but I would like to see a central listing if it exists.