iOS Ref
watchOS version by device
Apple Watch
Device
Released
First watchOS
Max watchOS
Series 5
2019
6
6
Series 4
2018
5
Series 3
2017
4
Series 2
2016
3
Series 1
Series 0
1
2014
1
4
1
βSeries 0β is a commonly used nickname for the first generation Apple Watch.