An early 'heads-up', a number of my ExtendScripts that were working under PS CC 2015.5 and PS CC 2017 no longer work. A number give inexplicable errors in the UI code.
I am investigating and will revert.
Some UI commands that work in PS CC 2018 under Windows 10 are errored without explanation in PS CC 2018 under High Sierra ... so it looks like an app/os compatibility issue.
No errors were reported after a reboot.