You could technically still build a driver against the old Driver interface and it will work because there’s a mechanism to bridge Driver to Device, but this API is now deprecated and unsupported.
There are some javadocs written for Device but it looks like none of the javadocs from the UA module are being published for some reason. I’ll have to look into this.
The OPC UA Device example is the recommended starting point if you’re building for 8.0. There isn’t actually much to the new device API because it’s mostly an extension of the Eclipse Milo address space APIs plus the additional context from being an Ignition module.
As always with the module SDK… it is what is. You’re welcome to keep asking questions in the forums and myself or others will answer what they can.