Effective Tuesday, April 26, SmartThings will begin rolling out the SmartThings Edge drivers in support of all newly on boarded Zigbee, Z-Wave, and LAN devices that connect to a SmartThings hub. These drivers run locally on the hub and deliver improved reliability and reduced latency compared to cloud-based device handlers know as Groovy DTHs. This transition marks the start of a gradual process that will include a small number of devices initially, but will expand to cover more devices over the coming months.
The steps required to onboard, (or add) devices with Edge drivers is unchanged from the existing experience, and according to the Developers, you should not need additional steps to complete this process.