According to @duncan , the physical/digital field, which is what most of the double tap smart apps rely on, has been deprecated because it just isn’t consistent. It only works for some models of switches, and even then, if the message was relayed through a repeater the field isn’t updated accurately. So they made a decision to no longer use that field in the company – created DTHs. If you read the thread I linked to above, you can add it back to your own handler, but then of course the device cannot run locally.
People who want double tap functionality and and are just starting out selecting switches can get it by selecting one of the models that provides double tap in the switch itself. This includes both the homeseer switches and the newest GE zwave plus models. I know that doesn’t help if you already have the older model GE switches installed, since they don’t do double tap in the switch, you have to figure it out with code, but it probably explains why SmartThings felt it was OK to drop the field now.
Make sure you express your concerns to support. SmartThings support staff don’t officially monitor these forums, so you need to make change suggestions through the official channel: