Trying to pair my new watch with my SE and I keep getting a message telling me I need to update my iOS. It's already updated to the latest.. what else can be done?

Hi

Your Apple Watch has previously been updated with watchOS 4 developer beta software.

It therefore cannot be paired to an iPhone running iOS 10.x

watchOS is not user-downgradable.

Your options include:

• Returning the Apple Watch to the seller for a refund.
• Waiting for iOS 11 to be released (due for release this coming autumn / fall).
• Participating in the iOS 11 public beta (this is not recommended for your main device):

  Apple Beta Software Program

• Contacting Apple Support or making a Genius Bar reservation to establish your available service options and any cost for returning the Apple Watch to watchOS 3.x..

Read here: If your Apple Watch isn't connected or paired with your iPhone - Apple Support

What iOS do you have? Tell us the number instead of it's the latest.

See Settings > General > About > Version > ???