The Google Search app, better known as Google Now on devices with Jelly Bean and up, is getting a huge update. After the update, the Google Search app will be able to listen for the “OK Google” hotword throughout the entire phone instead of just in the app, the Google Now Launcher or the few third party launchers that also include hotword support.
This is a huge change. The only time system-wide hotword detection has been available is on the Moto X, which used a special chip to do it. Unlike with the Moto X, this update won’t add the ability to wake the phone with your voice; your display has to be on. But Google is probably taking advantage of the existing chip in Qualcomm processors for this purpose.
The update may take a good while to roll out to you. In classic Google fashion, it may be a week or two. But check for updates often, as you may get it much sooner than that. Enable the feature in the app settings. Also, check out Audio History, a new feature that lets the app learn the sound of your voice. Tell us when you get it!