Apple watch REM tracking

Dear karenhastings,

Thanks for reaching out to the Apple community today! I want to share, You have to at least be on watch OS 9, and that is only supported with Apple watch series 4 or later. So make sure your Apple watch is up to date using this instruction link below: Update your Apple Watch - Apple Support

Thanks,

Luke

Watch series do you have? I think it might only be on series 7 or 8

Hmmm I really don’t know I have the series 8 and it works fine I would say chat apple support