Re: Apple watch SE compatible with Iphone 8?
Seems it is the operating systems (OS) that need to be compatible:
iPhone 8 with iOS 16 needs a Watch with at least iOS 9 ,
so yes, iOS 9 can be installed on Apple Watch SE (1st gen or later)
More info:
"watchOS 9 is compatible with these Apple Watch models:
- Apple Watch Series 4 and later
- Apple Watch SE (1st generation) and later
- Apple Watch Ultra"
"Updating to watchOS 9 also requires one of these iPhone models:
- iPhone 8 or later with iOS 16
- iPhone SE (2nd generation) or later with iOS 16"
Above is from the article: Update your Apple Watch - Apple Support
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Also: About watchOS 9 Updates - Apple Support says the latest version is watchOS 9.6.2