Apple unveiled iOS 8 on Monday at its Worldwide Developers Conference, but the company only scratched the surface of the hundreds of changes coming to its iPhone and iPad operating system.

There were several highlights at Apple’s keynote event, but there are even more hidden gems that the tech giant didn’t get to fully explain:

Hey Siri: Apple users will be able to summon their voice assistant in iOS 8 by simply saying "Hey Siri" — no need to press any buttons. It’s a direct reaction to Google, whose voice assistant can be activated on some Android devices with the words "OK GoogleNow."

Siri Shazam: By asking, "Hey Siri, what song is this?" it will recognize what songs are playing on home radio, in restaurants and elsewhere, using technology developed by Shazam.

Adjust message storage: In settings, user can adjust how long messages are stored, choosing from forever, one year or 30 days. The system will automatically delete non-eternal messages accordingly, freeing up storage space.

Emergency Card: Within Apple’s new Health app, users will be able to set up emergency cards containing their medical vitals. Paramedics, or anyone else, can bypass the screen lock to get the info.

Battery Usage By App: Some apps drain the battery faster than others. This feature will identify the culprits.

Camera exposure: For the first time, users can adjust the exposure setting before taking a picture, using a slider.

Camera timer: Like a traditional camera self-timer, this feature will enable users to set three or 10-second delays.

Camera time-lapse videos: This feature speeds up videos, a neat effect that can be seen in action in this YouTube video.

IOS 8 is available for download now for developers. The operating system will be officially released this fall, most likely alongside the next iPhone.