Today Google has announced yet another update for Wear OS (formerly known as Android Wear). It's calling it "H Update" although once you get it your watch won't display that, instead just telling you it's running Wear OS 2.2. It's unclear why this confusing naming was needed, but it is so nevertheless. Anyway, the new software packs a new Battery Saver Mode that will automatically turn on and only display the time once the level falls below 10%. This should further improve battery life, of course. When you're not wearing it, your watch will go into deep sleep mode after 30 minutes...
Source: https://www.gsmarena.com/google_announces_new_wear_os_update_with_improved_battery_saver_mode-news-34249.php