Garmin has begun rolling out a new feature to many of its current-generation smartwatches. Distributed through Garmin Connect rather than a firmware update, the new feature is related to tracking energy and recovery levels.https://www.notebookcheck.net/Garmin-quietly-rolls-out-new-sleep-tracking-feature-to-recent-smartwatches.821952.0.html
Garmin's upgrade policies is the main reason I switched to Coros. They abandon previous generation devices and exclude features even for top of the line Fenix and when no special or additional hardware is needed. Trying to make people replace their watch for some minor software feature update is a greedy strategy.
I echo what RW posted.
I'm still using a Fenix 5. At some point Garmin TOOK AWAY its sleep tracking feature, without notice. I liked, and used it.
Again, they just willy-nilly took it away.