@cauthren - This is not simply an OS port of an existing App. For OS updates of existing apps such as the iOS 11 release, this is quick and (relatively) easy for Dexcom to provide an update to the Dexcom G5 Mobile app so as to provide support for this.
However the G5 direct to the Apple Watch OS4 is not simply an update to an existing Dexcom App. This is an entirely new app. Completely different story. FDA approval is not required for Dexcom to support simple OS updates with no Dexcom App functionality change. But for the direct to Watch app? Will this require FDA approval?
In any event - don’t hold your breath on this one. Sure - I have no doubt it will arrive. Dexcom produces great products and they keep coming out with more. But this is a new product so it will take time. If FDA approval is required - that will only add more time before any release.
I could always be wrong.
Only time will tell.