iOS Ref

watchOS version by device

Apple Watch Released First watchOS Max watchOS
Series 7 2021 8 9 BETA
Series 6 2020 7
SE
Series 5 2019 6
Series 4 2018 5
Series 3 2017 4 8
Series 2 2016 3 6
Series 1
Series 01 2014 1 4

1 β€œSeries 0” is a commonly used nickname for the first generation Apple Watch.

See also