Yep! ZERO offers both iOS and Android apps for you to use.
Just search "ZERO Platform" in either App Store (iTunes or Play) or click one of the links below.
iPhone and iPad
Get ZERO for iOS in the Apple App Store:
You'll need to be on iOS 9 or later.
Get ZERO for Android phones and tablets in the Google Play Store:
You'll need to be on Android 5.0 or later.
Below is what the ZERO app looks like. If you're used to the browser version, the only major changes are that the sidebar hides behind a "hamburger menu" and the new post button is in the bottom, right corner of the app.