Windows Phone 8.1 adds voice assistant Cortana, gesture typing, and a new lockscreen

SAN FRANCISCO — During the company’s keynote address at its Build developer conference Wednesday, Microsoft introduced Windows Phone 8.1, the newest version of its phone operating system. The long-awaited release brings Cortana, a voice assistant to rival Siri, a new lockscreen and Action Center notification drawer.

Cortana replaces the earlier voice command feature in Windows Phone. Like Siri, Cortana is a she, and you can talk to her to search the Web using Bing, send messages, add notes, set reminders, get directions, and more. Like Google Now and Siri, you can ask Cortana questions, such as “How did the San Francisco Giants do yesterday?” It’s particularly good at answering sports questions, but you can ask it almost anything you want.

The new notification drawer, called Action Center pulls down from the top of your phone’s screen and gives you settings toggles. You can turn on or off Wi-Fi or Bluetooth, and see all of your notifications from your installed apps, such as text messages and new emails. Similar to iOS, you can customize which apps show up in Action Center.

The new lock screen shows the time and date, notifications, and upcoming calendar events. You can customize the background, like you could do in previous versions of the mobile OS. There are special animations that change how items move on the lock screen when you swipe to unlock your phone.

The Start screen, or home screen on your phone, now supports an extra row of tiles, even if you don’t have a large 6-inch phablet. Another major addition is that you can set a home screen wallpaper, and it will show up in your live tiles. You’ll still see the black space between the tiles, just like before.

The Word Flow keyboard (the stock keyboard that comes with Windows Phones) now gets gesture typing, and it works similarly to Swype and Swiftkey.

Aimed primarily at businesses, Windows Phone 8.1 adds a VPN feature, so you can access protected sites with your phone. The operating system also supports S/MIME so you can read encrypted emails.

Another addition to Windows Phone 8.1 is the Wi-Fi Sense app, which helps you connect to networks much faster by automatically accepting terms of agreement on free public Wi-Fi or enter credentials for networks you need to sign into. Microsoft has also improved its other Sense apps, which track battery use and phone performance.

Other features added to this update include a redesigned calendar, a new version of Skype, and Internet Explorer 11.

This is the fourth generation of the Windows Phone OS, and it replaces the earlier Windows Phone 8. That version was updated in October 2013 with Windows Phone 8 Update 3, which added a new row of live tiles to the home screen on larger phones, task-switching, and a driving mode.

Windows Phone 8.1 will roll out to devices over the next few months. Brand new devices will launch with it later in April and into May.

This is a developing story. Follow CNET’s live blog of the Microsoft Build keynote.