https://wccftech.com/a-quick-warning-for-original-apple-watch-owners-before-watchos-5-is-released/

We will be seeing the GM (Gold Master) release of watchOS 5 for Apple Watch in a few days and that should have everyone excited, until or unless you are a Series 0 user.

watchOS 5 is a minor upgrade, but it takes some giant leaps in certain areas. For example, Apple Watch will now automatically detect the type of workout you’re doing while also introducing features like the ability to use the device as a walkie-talkie between two Apple Watches. Sounds good, and that’s exactly our point.