9/17 UPDATE
A firmware update for Samsung SmartThings Hub 2018 and 2015 models will release to customers starting Wednesday, September 18th. This release version (27.9) is a hotfix for version 27.8 and includes additional improvements for LAN and Z-Wave device communication issues.
Your Hub will briefly go offline as it reboots and applies the update; most users will experience less than one minute of downtime.