Mobile email notifications are a nightmare. You always have new email. So as part of its big Gmail redesign, Google is aiming to make alerts for its mobile apps more useful. Starting with the Gmail iOS app (and soon for Android), the company is rolling out notifications for high priority messages. It's powered by AI and machine learning to determine relevant emails. The feature first appeared in Google's Inbox app, something that's serving as a testbed for new capabilities before they roll out to the much larger Gmail audience.