To say Microsoft's mobile operating system has struggled in recent years is an understatement. Android and iOS basically own the market. But the leading desktop OS vendor isn't giving in on the quest to disrupt the duopoly that currently dominates the smartphone landscape. A big part of its strategy ties in with its still-dominant position on the desktop. Though Windows 10 Mobile is not identical to Windows 10 on the desktop, it shares a great many features and capabilities with its big brother, and ties in tightly with other Microsoft services such as Office 365, Skype, OneDrive, and Xbox One. The OS also boasts standout capabilities like the Cortana intelligent voice assistant, Continuum, which lets you use your phone as a full-size PC, and Windows Hello, which lets you log in with your face. Can all this cool tech spur wider use of the third phone OS? Only time will tell.

How to Upgrade to Windows 10

Its recent release of Windows 10 Mobile for earlier-generation Windows Phone devices is further evidence that Microsoft isn't giving up on the mobile operating system market. At this writing, only a handful of the most recent Lumia models ran Windows 10 Mobile. Unfortunately, notable phones such as the Lumia Icon and the 41-megapixel-camera-toting Lumia 1020($149.99 at Amazon) aren't yet on the list.

Before upgrading, you should first head to Microsoft's How to Upgrade to Windows 10 Mobile page to see whether your phone is supported. To start the upgrade process, you first install the Windows 10 Upgrade Advisor app from the app store. This prepares the device for the upgrade, which is then installed as a standard phone OS update. If your phone isn't among those for which Windows 10 has been released, with some other models you can still enjoy the benefits of the new OS via the Windows Insider Program, though doing so installs the OS as prerelease software, meaning it may not be as stable and speedy as released software. I've been running it on a Lumia 1020 without issues, however.

There's one important caveat is for businesses that have deployed Windows Phones: Certain enterprise features such as Data Protection Under Lock and MDM capability to prevent saving and sharing Office documents won't work after the upgrade, so consult your IT staff before upgrading an eligible phone. And definitely don't use the Preview program for beta Insider builds, since beta isn't for mission-critical work.

Interface

Like Android, Windows 10 Mobile lets third-party apps (such as weather apps) take over the lock screen image. You can also choose quick-status icons to appear on the lock screen, such as your numbers of emails and messages. You can also select one app to show detailed status—the Calendar is a typical choice. You can swipe down from the top to see your notifications and quick-access tiles, such as airplane mode, Wi-Fi, rotation lock, and more. Notifications on the lock screen can set to private, per app, so that, for example, a Facebook message's text doesn't appear on it.

Passing the lock screen, you get to the tile-based interface, which is more finger-friendly than the smaller icons in other mobile OSes. You can adjust the opacity of the tiles so that your beautiful background image shines through. The upgrade also brings new tile layouts and background options. You can now group tiles by dragging one on top of another, just as on iOS and most Android phones.

Swipe left from the home screen, and you reveal all app tiles, which is mighty convenient if you're using the phone with one hand. You can also tap on an alphabet letter to display the whole alphabet, letting you easily get to all apps that start with a certain letter. If that's not enough, there's now a one-handed mode that slides the interface down, especially useful on big phones such as the 5.7-inch Lumia 950 XL or the earlier Lumia 1520($215.81 at Amazon). Another welcome update is that the full app list shows your most recently installed apps on top.

Windows Hello

A clever party trick on Windows 10 Mobile is its ability to log you in with your face, using Windows Hello. It's also handy if you're wearing gloves or have your hands full. The Lumia phones that support it actually scan your iris, so they can't be tricked by someone holding a picture of your face up to the phone, since it uses infrared illumination and detection. As with Apple's Touch ID fingerprint scanning, the biometric data never leaves the phone and ties in with Passport, Microsoft's public-key authentication system, which enables logins to third-party services. On the desktop, Hello can work with fingerprint scanners or specific 3D camera setups such as Intel's Real Sense.

Other New Perks

Windows Phone 8.1 users already have Cortana(Free at Apple.com), but the update brings a few desirable new features, some of which are merely catch up with Android and iOS. One such is that the microphone icon, which lets you enter text using your voice, appears in every text box you see on the phone. Previously, it only worked in a few apps like email and text messaging.

Speaking of the keyboard, the Windows 10 Mobile keyboard is unmatched in my experience: Not only is the shape writing, in which you trace a finger around the keyboard to spell a word, much better than that of any iPhone add-in keyboard (and equal to the also excellent stock Android keyboard's), but it's the only default keyboard with a cursor-direction button (reminiscent of the ThinkPad's pointing stick).

Settings are much clearer, as the long list in Windows Phone 8.1 has been replaced by grouped, streamlined, and searchable choices. The All Apps page also gets a search box, and your most recently installed apps appear at the top of the list. When you search for an app in this view, you get a Search Store option if the search doesn't turn up anything in your collection.

Universal Apps

Nowhere is Microsoft's strategy of one OS to rule them all more apparent than in its Universal Windows App platform. The idea is that developers can build apps that run on Microsoft's far more successful desktop/laptop OS that also run on tablets, smartphones, the Xbox, and even the HoloLens. Of course, it's not the exact same code running on each device—just as iOS on an iPad differs from iOS on an iPhone. But about 80 percent of the coding in a Universal is common to all platforms.

Universal Apps may blaze a path towards more app availability, and we've already seen big titles like Dropbox, Facebook, Instagram, Netflix, Pandora, Twitter, and Uber. The biggest holdout seems to be Snapchat(Free at Apple.com), so teens wanting to hide their messaging from parents may prefer another phone OS. Another, possibly more concerning issue is that many Windows Phone apps suffer from less functionality than their iOS and Android counterparts. For example, the Words With Friends app doesn't include a dictionary or word strength features.

Included Apps

You do, however, get powerful new included apps with Windows 10 Mobile. The Photos app can automatically create albums, and offers a Living Photos feature that's awfully similar to iOS's Live Photos. The Windows Phone camera app also lets photo buffs choose manual settings like shutter speed and f-stop, something not available to iPhone users.

The new Edge Web browser is fast and (mostly) standards-compatible, and its interface is an improvement: I prefer its tab handling to that of other mobile operating systems. A really helpful tool in Edge (and one shared by iOS's Safari, but not by Android's Chrome) is reading mode. This strips out distracting ads and auto-play video, which may be even more helpful on mobile than on the desktop.

Edge also has a Reading List feature for saving articles for later perusal, and managers for favorites, history, and downloads. You can find other browsers in the Windows Store, including Opera Mini, Maxthon, and UC Browser, though unfortunately there's no Firefox for Windows Mobile.

The new Outlook Mobile mail app is a big improvement over that in Windows Phone 8.1: You can swipe left and right to archive and flag messages (or change what these actions do to taste), and the app now supports multiple mail accounts from any mail provider, including Gmail and Yahoo as well as Outlook.com or your Exchange or private mail server. Switching among accounts is simple whether you're reading or sending. Unfortunately, you don't get the iPhone's version of Outlook Mobile's(Free at Apple.com) Focused inbox, which I like.

Maps in Windows 10 Mobile include turn-by-turn spoken directions for driving, public transport, or walking (alas, no bike routing). As with Siri or Google Now, you can ask Cortana to get you directions to a destination, and Maps will get you going. You can download maps for offline navigation, and (thankfully) turn off the warning beeps should you exceed the speed limit. An upcoming update now in the prerelease version of Windows 10 Mobile will move the controls to the bottom for easier one-handed use. The maps also have a super-cool 3D cities view, letting you fly around major metropolises like an action hero.

Music and video are also provided by Microsoft apps—Groove and Movies & TV. Both offer fully stocked repositories of both top hits and old favorites. With Groove, you get unlimited access to any music you want to play, not only on the phone, but on Windows 10 PCs, iOS and Android devices, and Xbox. Movies & TV works similar to iTunes, through which you rent or buy titles individually.

Mobile versions of Microsoft Office($99.99 at Microsoft Store) apps—Word, Excel, PowerPoint, and OneNote—come free with Windows 10 Mobile, and your documents for all these sync with OneDrive. The interfaces are surprisingly functional, given the small screen size. They even include Office 2016's real-time collaboration and its Smart Lookup feature, which accesses Web knowledge on selected text without taking you out of the app.

Store

Windows 10 Mobile's app store has been spruced up since the last version, and more closely resembles the store on Windows 10 for desktops. Featured and top apps are clearly accessible, and a left-side hamburger menu now shunts you to Apps, Games, Music, Movies & TV, My Library, Updates, or Payment methods. That's right, you can now purchase music and video in the store as well as apps, just as you can in Google Play, iTunes, and on Windows 10 on the desktop. Though Windows 10 gets dissed for a dearth of apps, it offers a ton of games, including both casual and mobile versions of major Xbox titles.

Cortana

Cortana combines the personality of Siri with the predictive functionality of Google Now. You invoke her in one of three ways: Tapping her tile, holding down the search magnifying glass button that's always preset at the bottom right of the screen, or (new for Windows 10) you can turn on listening for you to say "Hey Cortana!" Each evening when I'm about to leave for work, Cortana lets me know how long my commute home will take. In the morning, she shows me sports scores, news, and weather for the day. I can ask her to tell me a joke, and she comes up with something from a deep repository, some funnier that others.

Unlike Apple Siri and Google Now, however, you tell Cortana exactly how much personal information you want to share with her, using the Notebook. This includes 15 sections for your interest info, such as food you like, sports, health, travel, special days, and places. Filling in the last with your work and home addresses is what enables her to predict your commute.

In addition to fielding spoken questions, Cortana shows your Daily Glance. This includes news, sports results, weather, and any meetings on your schedule.

Cortana does other things you'd expect of an assistant, too. Say, "Remind me to buy aspirin when I'm at a pharmacy," and the notification pops up when you walk into a Rite Aid or other similar store. As with Siri, you can dictate and send text messages and emails with Cortana. Tell Cortana to take a note, and she'll open OneNote and enter whatever you say. You can then read that note on your PC in OneNote 2016, on your iPad in OneNote Mobile, on the Web, and anywhere else you have the app installed.

Reminders in Cortana can be based on Time, Place, or Person. The first is self-explanatory, the second is like the aspirin reminder noted above, and the third pops up a notification if a specified contact calls or texts you. In this release, Cortana loses the ability to search local things like apps and emails, but app searching in the all apps page is simple. I expect Microsoft will add those capabilities back, since they're available on Windows 10 on the desktop.

Continuum

For me, Continuum is Windows 10 Mobile's most remarkable feature. It brings to life the dream of using a smartphone to power a desktop scenario. Sure, other phone OSes can mirror their screen to a big TV via Apple TV or MiraCast (which Windows Mobile also supports), but this OS actually reformats the interface elements to work on the larger screen with mouse and keyboard. This goes much farther towards using smartphones for all computing than Android N, which merely offers dual windowing (and which makes little sense on a phone, in my opinion). Hardware vendors such as HP, Sony, and others have even started offering Windows 10 Mobile devices designed specifically to power laptops and desktops.

Continuum can work wirelessly using MiraCast (for the full experience, a device should support Windows MiraCast extensions) or with a wired hub, such as the $99 Microsoft Display Dock. I tested Continuum with both the latter and also wirelessly to a Roku 2($219.00 at Amazon) box connected to an HDTV. So if you're at a hotel with a smart TV, Windows 10 Mobile lets you treat yourself to a big screen for viewing that spreadsheet.

One of the coolest things about Continuum is that while you're using it to power a monitor-and-keyboard system, you can still use the phone as a phone. Also cool is that the phone's screen can turn into your trackpad for the bigger system. You can also connect Bluetooth mice and keyboards to the phone. The Universal apps are part of what enables Continuum: When on a phone, a universal app looks and behaves like a phone, on a bigger screen like a PC app.

Notifications still appear on the phone, rather than the big screen, since it's likely others can view the big screen. But you can open the Action Center on the big screen, where you'll see them. One disappointment: The apps run full-screen only, though you can switch among them via the taskbar, or even via multiple desktops! Think about that! The phone itself doesn't (and shouldn't) have multiple desktops, but when projecting to a Continuum screen, multiple desktops are available.

Ecosystem Tie-ins

Though Microsoft has been aggressively making its mobile apps available on Android and iOS, there are still some advantages only Windows Phones get. OneDrive functions like a combination of iCloud and Google Drive. Like the former, it can back up your phone, apps, data, and settings. Like the latter, it serves as cloud storage for documents and enables real-time collaboration. You can open your OneDrive content on any platform, including iOS, Android, and the Web. OneDrive's photo prowess seems underappreciated, offering object recognition, maps for geotagged photos, and EXIF camera data.

The Xbox app is a Windows 10 exclusive (though Xbox SmartGlass is on the other OSes). Here you can keep up with your gamer buddies through an activity feed, achievements, friends list, alerts, and messages, as well as watch Game DVR clips and connect to an Xbox One($200.00 at eBay). Later, the app will include live TV streaming, according to Microsoft.

Skype is also baked into Windows 10 Mobile, and it's integrated into the same messaging app you use for SMS—just like Apple's iMessage has long lived in the same place as text messages. Skype Video is now a separate app (that's right, just like the iPhone's FaceTime)

Perhaps of less universal importance, Windows phones get preferential treatment with the Microsoft Band 2. Though iPhones and Androids can connect to them to show notifications and sync health-monitoring data, if you use a Windows Phone with your Microsoft Band 2, you can talk to Cortana on your wrist, just like Maxwell Smart, James Bond, or Dick Tracy! (Or like an Apple Watch, which costs twice what a Band 2 does.) Even if you don't have a Band 2, you can use the Microsoft Health app to track steps (just like you can with iPhone and most Androids.)

Platform Advantages

Windows Phone shares a platform advantage with iOS over Android: Like Apple, Microsoft has more control over delivering updates to phones. At this writing, according to Google, only 2.3 percent of Android phones run the current version, Marshmallow. With a U.S. share of 52 percent (comScore), that means that there are actually more Windows Phones in use than phones running the current Android version (5.4 million vs. 2.4 million)! If you use an iPhone or Windows phone, you're much more likely to be running the current OS version than with Android.

Another platform advantage is security. Noted security expert Eugene Kaspersky (of Editors' Choice Kaspersky Internet Security fame) has said that Windows Phone is "much better operating system than the rest (iOS, OS X and Android)" in terms of security, with far fewer vulnerabilities.

A Third Smartphone Option

If you don't need to have the same kind of smartphone as everyone else, and can live without some of the hottest new apps, Windows 10 Mobile has a lot of appeal. It delivers some unique features, including Cortana, Continuum, Windows Hello, and tight integration with other Microsoft services such as Office 365 and Skype. Apple's iOS 9 wins PCMag's mobile operating system Editors' Choice, however, because it offers the most and latest apps, as well as the most polished interface.

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