If you have an original Watch (Series 0, 1st Gen) you’ll be aware that it is no longer supported by watchOS 5, which is required by Siri Shortcuts to in order for you to be able to access the watch app.
I’ve half a dozen Workflow apps I rely on a day-to-day basis which I generally trigger via my Watch which now, as I’ve updated my iPhone to iOS 12, I can’t access. The old Workflow app doesn’t seem to be listed in the App Store anymore so I can’t see any way of getting it back again without restoring by iPhone to a pre-iOS 12 backup.
Had I have realised this I’d have held off my upgrade. I hindsight this seems obvious, but too late now. I plan on getting a 4th generation Watch by based on the delivery times that’s going to be a few weeks out.
Just a head’s up if you’re in a similar situation and haven’t updated yet.