Editors' note, March 12, 2015: This review has been updated with details about Android 5.1 Lollipop.
The first real face-lift since Android 4.0 Ice Cream Sandwich, Android 5.0 Lollipop brings a significant design change without straying too far from the familiar Android experience.
For Lollipop, Google crafted a standout aesthetic that's both as modern as iOS 8 and uniquely its own. What's more, the new design is everywhere in the OS, making Lollipop feel cohesive, all of its parts fitting together perfectly.
There are few blockbuster extras in this release, since Google added mobile payments, unified search and support for third-party keyboards ages ago, but the core features are all still there, and they're better than ever.
The most obvious change in Lollipop is the fresh design aesthetic, called Material. It changes nearly every single thing about how Android looks, from the setup menu, app drawer and notification shade to animations and icons. Even the onscreen back, home and recent app buttons look different; they're now simple geometric shapes. Though Material is a significant design shift, you'll likely see the most extreme changes only on Nexus devices because smartphone manufacturers often use custom skins to change the look of Android.
Material is dynamic, and it responds to touch in new ways. A great example is when you reach the end of a menu, you see a transparent gray shading on the screen that moves as you move your finger on the screen. In fact, most button presses trigger a shading on the screen that radiates outward, showing you that the device has registered your touch.
Animations are everywhere, with expanding and condensing effects when you open and exit the app drawer, a zooming effect when you swipe to unlock the screen and a sliding animation when you swipe down from the top of the display to view notifications and the quick settings menu.
What you'll notice most is that Material uses bright, rich colors. Overall, the operating system looks flat with few of the faux-3D effects that were all the rage several years back. As Apple did with iOS 7, Lollipop abandons skeuomorphism and in its place, there's an artistic yet unmistakably digital look. You'll also find playful illustrations throughout the Google apps, adding some playfulness that iOS lacks.
Another important design theme is cards, where notifications, the app drawer, and the text in many apps are set on their own card that's then laid on top of a different background. Cards were made popular in Google Now, and now they're a bigger part of Android's style.
Material makes its way into nearly all of the stock Google apps, and you'll see colorful menu bars and whimsical illustrations that introduce you to new features.
Gmail and Calendar got the most profound makeovers in Lollipop, by way of new layouts. Gmail, for instance, gets a simplified inbox and updated side menu. Calendar also gets a cleaner design, with fewer distractions and with full-color seasonal themed backgrounds for each month. If you don't like those backgrounds, you can turn them off, but I think they add a lot of personality to an otherwise dull app. Calendar also helps you create new events by offering suggestions as you type.
Notifications have always played a big role in Android, tucked away in a menu at the top of the screen that could be swiped out of sight. Lollipop keeps that same setup, but also adds notifications to the lock screen, similar to what you see on iOS and Moto Alerts on Motorola handsets.
Each alert appears as a card that can be swiped down on to expand the message. You can also swipe to clear it away or tap it to interact it with it, which will open the corresponding app after you unlock the screen. To protect your privacy, you can control whether you get notifications from on the lock screen or not, and if those notifications reveal any sensitive data, such as the content of a text message.
The card design also appears in the notification shade, which you swipe down from the top of any screen to reveal. A nifty new feature allows you to press and hold individual notifications to access the app's notification controls.
One of my favorite new notifications features is that you can, on an app-by-app basis, decide which ones trigger notifications and which ones don't. That's long been an feature in Android, but the option was hidden away in individual app settings and not all that easy to find. Now, there's a dashboard in settings that makes it infinitely easier to turn off app notifications. Furthermore, in that menu you can turn on priority notifications for certain apps. By doing that, notifications from those apps will still come through when your device is in Priority mode (more on that below) and appear at the top of your notification lists.
The new Priority mode, which you can turn on with your device's volume rocker or in settings, only shows the most important notifications. It's like a Do Not Disturb mode, in which only calls, event reminders, text messages and alarms will get through. Google is now calling these types of alerts Interruptions, separating them from other app notifications.
With Priority mode, you can even select to receive Interruptions only from certain contacts. If you don't want to be disturbed by anything, including alarms, select "none" from the notification menu when you press the volume rocker, which will block everything, including Interruptions.
Another addition is the heads-up notification, which shows small pop-up alerts at the top of the screen. You can interact with or respond to the notification and then move on, without even needing to open the notification drop-down menu. Or, if you'd rather not deal with it right now, just swipe it up to store it in your notification menu for later.
Currently, Interruptions (phone calls, alarms and texts) trigger heads-up notifications, but app developers can use them, too.
Multitasking gets a makeover in Lollipop. Doing away with "recent apps," a new menu called Overview shows apps that are running in the background as a stack of cards, instead of the previous list view.
The design is similar to what you see when browsing open tabs on Chrome's Android app, and you can scroll through the stack to switch between apps quickly. In addition, Overview shows you multiple tasks within individual apps. For instance, in Gmail, if you were drafting a new email as well as checking your inbox, Overview will have two Gmail tabs shown for these separate tasks.
It's a much faster way to browse open apps than the previous recent apps menu, which took up more space on the screen, and yet didn't always show a legible preview of what was going on in the app. With Overview, you can easily see what you were last doing in each app.
My only disappointment with Overview is that you cannot clear out all of your recent tasks at once, nor can you swipe away more than one app at once. I recommend that you swipe away each card, as opposed to tapping the X's that appear, since their touch target is rather small and it's easy to accidentally open the app instead of clearing it.
Android Jelly Bean introduced multiple user profiles for tablets, and now phones can use them, too. You can create multiple accounts for yourself, your family and specifically your kids, and control which profile has access to which apps and settings. What's more, if you don't have your phone with you, you can now log in to another Lollipop device to access your contacts, messages and photos using Guest mode.
Guest mode lets someone access only certain parts of your phone or tablet but not others. It's a completely self-service model, meaning other people can be recognized as a guest without the owner being present. Once Guest mode is activated, only certain apps and content will be made available. Afterward, you can end their guest session and all account activity will be erased.
Another device-sharing feature is screen pinning, where you lock an app on the screen, hand the device to someone else, they won't be able to leave the app to explore the rest of the device. You turn on this feature from settings, and then head to Overview to pick the app you want to pin.
Anyone can unpin by holding the Back and Overview buttons at the same time. However, if you have a PIN or pattern screen lock set up on your device, you can use it to prevent someone from unpinning the screen without your consent. This feature comes in handy for putting a game on your tablet and handing it over to your kid, or for kiosk displays, where you want to lock a promotional app on the screen.
Just as the notification shade gets a makeover, so does the swipe-down quick-settings menu. It now lives just above the notification shade, and has a nice sliding animation when you open it, which you do by swiping past your notifications or swiping down with two fingers from the top of the screen.
The menu houses controls for a flashlight, airplane mode, screencasting and the screen rotation lock. There's a brightness slider at the top with improved Wi-Fi and Bluetooth toggles below that let you turn these services off and on, as well as quickly access more advanced settings. There's also a shortcut for your phone settings and to switch user accounts.
Lollipop adds a new Battery Saver mode, which clocks down the CPU, limits vibrations, reduces the ambient light and turns off background data when your device needs a little extra juice. You can turn it on manually or program it to turn on automatically when your battery drops too low, and Google says it can add up to 90 minutes of extra life.
You can now also see how much time your phone has left before it's fully charged when you plug it in, and in the battery settings menu you can see approximately how much time your phone's battery has left before you need to charge it. That's a really helpful feature when you're short on time and battery life and want to see how long it will take you get the power you need.
Another addition to Lollipop isa new way to unlock your device, called Smart Lock, that uses any compatible Bluetooth device -- such as the Moto 360 -- or an NFC tag, to automatically unlock your phone. With the feature enabled, you phone will automatically unlock when it's close to the Bluetooth device or you tap an NFC tag. When you're too far away from it, your PIN, password or pattern lock will switch back on.
Using Bluetooth or NFC to unlock an Android device isn't new, but you used to have use a separate app to do it. It's nice that it's now baked into the operating system.
The security features don't stop once you unlock your device. Encryption is now enabled by default on all Android phones and tablets running 5.0 Lollipop, which helps keep your them safe by scrambling the data on it. That data can only be unscrambled with a special key, which you access with a password you create. Older Androids have encryption as a security option, and it's easy to set up, but now you won't even need to think about turning it on.
In March 2015, Google pushed out its first major Lollipop update, version 5.1. While it brings many behind-the-scenes changes, there are just a few that are noticeable.
First, 5.1 introduces official support for dual-SIM phones, letting you switch between SIM cards and networks within the OS. Dual-SIM Android phones have been around for many years now, and Google is finally giving them some attention with the update. Many people use dual-SIM phones while traveling or to separate work and personal wireless service on one device. This feature goes along with Google's Android One initiative, in which the company has committed to get more inexpensive, yet feature-rich Android phones into developing markets.
Google beefed up security with 5.0 Lollipop and took it a step further with 5.1 and a feature called Device Protection. Now, if you your phone or tablet gets stolen or lost, the device will stay locked even if someone resets it. You'll need to log in in with your Google account on that device to unlock it. Device Protection will be available on the Nexus 6 and Nexus 9, as well as other devices that ship with 5.1.
The next addition is High Definition voice calling between two 5.1 phones. This enhances the call quality on your phone, making calls sound crisper and clearer. Unfortunately, you'll need to be on T-Mobile or Verizon to use HD Voice, and the person you call will also need to have a phone running 5.1 on either of those networks.
Another feature added, one that's a bit hidden in the change log, allows your phone's LED indicator light to still flash when you have a missed notification, even if you've turned off Interruptions.
Finally, Lollipop now lets you connect to Wi-Fi networks or pair with Bluetooth devices from the quick settings menu, instead of going into the regular settings menu. It's a small update, but one that will save time when you need to connect.
Android 5.1 is rolling out to Nexus devices now, including the Nexus 6, Nexus 9, Nexus 7 (2013 edition), Nexus 5 and Nexus 4. The exact timing of these updates is usually left up to your wireless carrier, and both Sprint and T-Mobile have confirmed that 5.1 is on its way to devices now.
With every new Android update, there are tons of small changes here and there throughout the operating system. Here's a rundown of the other added features in Lollipop:
Google announced Lollipop with the launch of the Nexus 6 smartphone and Nexus 9 tablet, and those devices are the first to run Android 5.0. The first two Android flagship devices released in 2015, the Samsung Galaxy S6 and HTC One M9 , will also ship with Lollipop on board.
The Nexus 5 , Nexus 7 , Nexus 10 and Google Play Edition devices, including the HTC One M8 and Moto G , are getting the update as well. LG, Sony and Motorola are also slowing pushing out the update to their smartphones, though so far it's only available in certain markets, such as Mexico for the Moto E and the UK for the LG G3.
As with most Android updates, it's up to your carrier to send out the update, so you might need to be patient for a few months. And, keep in mind that if you have an older device, you might never get the official update.
Though Google made a commitment with KitKat to make it easier for both premium and budget devices to get the most up-to-date version of Android, I expect that many phones will have to wait for Lollipop and that companies will continue to build new phones running Jelly Bean or KitKat for the foreseeable future.
Not every feature will appear on all phones, but most modern Android phones or tablets will get a taste of Lollipop in one way or another. Google's core apps, including Gmail, Calendar and Maps, have been updated with Material design. I also expect many of Lollipop's star features to arrive on other devices, such as user accounts, priority mode and default encryption.
For its newest flavor of Android, Google took a big bet on design that paid off. Not only is Material bright and welcoming, it's downright fun to use, thanks to many subtle design flourishes and eye-catching animations. It's not immediately obvious when you first look at the update, but Material's best attribute is how everything fits seamlessly together, with a cohesive design that reaches all corners of the OS.
Android's existing core features -- notifications, security, sharing and battery life -- also received improvements, making them more useful. Priority mode in particular feels like a killer feature, since it's a smarter version of Do Not Disturb that's as easy to turn on as changing your ringer volume.
With the three major mobile operating systems -- Android, iOS and Windows Phone -- all offering roughly the same features, Google looked to the onscreen experience to make Android stand out. When picking a phone to buy today, it's no longer a question of which OS is best, only which one is best for you. With Lollipop, you get all the features, plus a polished design that doesn't take itself too seriously.