Apple’s iOS 17 might look like a mere numerical upgrade at first glance, but it actually houses several hidden features that could significantly enhance your user experience. Here is a curated list of 17 under-the-radar functionalities that you should definitely know about:

1. **Customizable Lock Screen Widgets:** Beyond the visible changes to the lock screen, iOS 17 allows users to add custom widgets for deep personalization.

2. **Shared Photo Library:** A new way to share photos with family members selectively or automatically, based on specific criteria.

3. **Undo Send in Messages:** Sent something by mistake? iOS 17 gives you a brief window to recall sent messages.

4. **Siri Offline:** Now Siri can handle many requests without an internet connection, thanks to on-device processing.

5. **Safety Check:** This feature helps users quickly reset all access they’ve granted to others in scenarios where personal safety is a concern.

6. **Wi-Fi Password Viewing:** No more guessing; view saved Wi-Fi passwords right from your Settings.

7. **Duplicate Photo Detection:** iOS 17 automatically detects and bundles duplicate photos, helping you to keep your library organized.

8. **Background Noise in Calls:** The new OS includes ambient sounds that can play in the background during calls for more natural-feeling conversations.

9. **Live Text Video Support:** Live Text now extends to videos — pause any video and interact with text just as you would from a photo.

10. **Quick Note App Access:** Access the Notes app rapidly with a swipe or quick gesture from the lock screen.

11. **Dictionary Enhancements:** Apple has vastly improved the built-in dictionary with more definitions and contextual examples.

12. **Drag and Drop Between Apps:** Enhanced drag-and-drop capabilities make it easier than ever to transfer images, text, files, etc., between apps without multiple steps.

13. **Hidden Album Lock:** The ‘Hidden’ album in Photos now requires authentication, so prying eyes can’t access your discreet photos so easily.

14. **Smart Folder Organization in Mail:** Mail app introduces smarter folder categorization and organization for better email management.

15. **Adjust Video Playback Speed:** Control how fast or slow you consume video content directly in Apple’s default video player.

16. **Fitness App for All iPhone Users:** The Fitness app isn’t just for Apple Watch users anymore; it’s now available to all iPhone owners on iOS 17.

17. **Multi-Stop Routing in Maps**: For those who need to make several stops during their trips, this awaited feature brings convenience by allowing multi-stop routing within Apple Maps.

These features signify Apple’s continued effort to provide both front-facing improvements and subtle enhancements that streamline everyday mobile usage, rarely getting the spotlight but altogether offering a powerful cumulative impact on how we interact with our devices daily.