[SaveFerris]

Oh, that I already know (its general capabilities).

I’m just wondering what is encrypted. Certain messages?

Any voice they’re speaking is already captured.

[TexasGator]

“Any voice they’re speaking is already captured.”

Not that anyone knows.

[Swordmaker]

Oh, that I already know (its general capabilities).

I’m just wondering what is encrypted. Certain messages?

Any voice they’re speaking is already captured.

In addition to all personal data stored on the iPhones and iPads being encrypted to 255 bit AES encryption standards, you'll find what's also protected here:

http://www.welivesecurity.com/2015/09/10/ios-9-security-boosted-2fa-stronger-passcode/