 Did you ever wonder how Chrome updates work, and you know what exactly is Chrome Canary? Well as you might know, there are actually four varieties of Chrome available at any one time. You might also hear these called Chrome Release Channels. So first, there's Chrome Canary, then that's the most experimental Chrome channel with all the latest new features added without much testing. Next comes Chrome Dev, and there's more testing at this stage, but it's still likely to have some bugs. Chrome Beta comes after that, and this is even more polished. And finally, after full testing and checking that everything works as expected, you get Chrome Stable, which is probably what you're using right now. So hi, I'm Sam Dutton, and I work with the Chrome team as a developer advocate. And in this video, you'll learn how Chrome tests new features and rolls out updates. You'll find out how Chrome Release Channels work, and why you might actually want to use Chrome Canary. Now I won't go too deep technically, but you should get a good understanding of how and why we release new versions of Chrome. But first, I'd like to explain why we need all this. Think about how you release stuff. For example, you're right, I don't know, a really important email, you check it a thousand times, and finally, you press send, only to find you made a spelling mistake and you got someone's name wrong. You know, it's like, ah, anyway, software is like that only worse. Chrome has thousands of contributors, millions of lines of code, and billions of users. When you release a new version of software like Chrome, it just has to work. Popular complex applications need really robust processes to ensure that new features and changes to code avoid adding bugs and causing unexpected side effects. So you need really strict mechanisms for testing software before you release it. But of course, in the real world, you also need to expect the unexpected after software is released and when real people start using your product at scale. And this is particularly true for web browsers. Browsers, you know, don't work in isolation. They need to cope with the quirks of millions of websites changing constantly and all kinds of user behavior, expected and unexpected. We could release a new version of Chrome to billions of users and dozens of languages across multiple operating systems and a gazillion different devices, all in one big bang and just, you know, cross our fingers and hope for the best. What could possibly go wrong? Well, of course, we don't do that. Instead, we begin by experimenting with a change or a new feature in Chrome Canary. In other words, we update part of the code. And of course, some changes never make it any further. But if all goes well, we update Chrome Dev with the change and then Chrome beta with more and more testing and more checks until finally the changed code makes its way into Chrome stable. Chrome stable is the Chrome release that just about everyone uses. And, you know, most people just call it Chrome. So just to sum up, there are actually four Chrome applications available at any one time. Chrome Canary, Chrome Dev, Chrome beta and Chrome stable. And, you know, that's the same on mobile as well as desktop. And each one of these is called a release channel. And I'll tell you later how you can actually install them. So let's look at these in a bit more detail. First up, Chrome Canary. And this version of Chrome is like the proverbial Canary in the coal mine with a logo to match. Chrome Canary helps us try out changes with real users and developers to test for glitches before they become a problem. Chrome Canary is released daily. Changes and new features get added with minimal testing. You know, Canary can and does break. Occasionally, a Canary build may even have a bug that makes it crash or be completely unusable on some sites. But of course, the good thing about releasing Canary every day is that bug fixes can be shipped quickly too. So why would you want to use Canary? Well, you know, if you like to live on the edge, this is the version for you. But seriously, Canary is really useful for developers and enterprise users needing to test new features. Just bear in mind that some features may never make it beyond Canary. That's one of the reasons Canary is actually so useful. Now, Chrome Dev Channel is the next stage in the process. New versions of that get released once or maybe twice a week. Chrome Dev shows what the Chrome team is working on right now. Now, this version is still pretty fresh. It gets more testing than Canary. But you know, you're still likely to find bugs and other glitches. So next up is Chrome Beta, which is far more, well, just more polished and carefully checked and tested. It's updated about once a week with major updates every four weeks. Chrome Beta gives you access to improvements and new features more than a month before the stable channel will get them. And that's the final stage of the Chrome release process, Chrome Stable. Changes and updates only make it into stable when they've been through a process of rigorous automated testing and manual checks. Now, this is always the Chrome channel you should consider as default and current. The channel installed by the vast majority of users. And like I said before, most people just call this Chrome. Anyway, one thing to bear in mind here, within each release channel, there are multiple versions at any one time. But they each keep the same major number throughout one release cycle. So while I was writing the script for this video, Chrome Stable was on version 101, Chrome Beta was on 102, Chrome Dev and Chrome Canary were different versions of 103. Now, if you're actually curious about the version you're using, take a look at the Chrome version page. You can see in each Chrome channel what the version is and, you know, observe how that changes over time. Now, Chrome engineers have access to some other mechanisms to help enable new features and fixes to be rolled out quickly and safely. I'm talking about field trials, telemetry and components. Chrome is designed so that some new features can be enabled or disabled with field trial flags. So here's how it works. The Chrome browser application running on your device periodically checks Chrome's back-end servers to see if there are any changes to field trial flags. Now, depending on the flags returned by the server to the browser, features can be turned off or turned on in Chrome running on your device. For Chrome, field trials are also called Chrome variations. Microsoft has a similar system for the Edge browser called ECS. The Chrome variations mechanism enables new features to be enabled for some Chrome users and not others and turned off if necessary. You can find out more from our upcoming video, what are Chrome variations? So now, whenever rollout begins for a new feature, the Chrome team, of course, watches very carefully for user feedback. But Chrome also uses what's called telemetry to check for unexpected behavior. The Chrome application automatically monitors itself and sends reports to the Chrome back-end servers. And this telemetry data might include memory usage, page load times, or the usage of a browser feature. Data can be compared for the group of users who have a new feature and the control group of those who don't. And that way, if something problematic happens with a new feature, Chrome engineers can turn it off while they're working on a fix. Chrome also uses components. For example, Chrome has a module to enable playback of copyrighted video. Components can be updated automatically without needing the browser to be restarted. And that's particularly important for security features. Now, Chrome doesn't just release a new version to all users and hope for the best. Instead, Chrome uses what are called staged rollouts. Now, that means that initially, only a small number of users for each release channel get an update, maybe only like 1% to 5% to start with, gradually building up to 100%. If something goes wrong, the rollout is paused while the Chrome team works out how to fix the problem, either by turning off an experimental feature, updating a component, or shipping a code update which is called a re-spin. So how can you install a different version of Chrome? Well, that's easy. Just go to the Chrome release channel page and download whichever version you want for desktop or mobile. You can install them all if you really want. And by the way, you might be wondering what Chromium is. Well, Chromium is the open-source browser project on which Chrome and other browsers are based, including Edge, Samsung, Internet, and Brave. Browsers have become so complex to build and maintain that basing the code on an open-source project has become a common pattern. For example, the Safari browser uses WebKit. And Chrome adds some additional features to Chromium, such as additional video codecs, support for copyright content, and automatic updates. Now, you can even install Chromium itself if you want. Just bear in mind that using Chromium as your browser can be a bit of a roller coaster. One last thing. You might also have heard of Blink. Now, that's the layout engine or rendering engine used to transform webpage code and resources into the pages that you see and interact with. And likewise, V8 is the open-source engine developed by the Chromium project to run JavaScript code. Anyway, speaking of automatic updates, well, how does that work? Well, as some of you like me might be old enough to remember, software releases used to happen quite rarely, maybe only every few years even. And you know, you had to buy updates and install them yourself. It's a real pain. Anyway, Chrome gets updated frequently and automatically. And you know, you don't need to download anything yourself or do anything special to update Chrome, except to restart the browser. You might see an update button in Chrome if there's an update available and you haven't restarted for a while. Our major updates happen in Chrome Stable every four weeks and minor updates more frequently. New versions are not just about adding new features, of course. Yeah, we also need to fix bugs, make improvements to existing features, make code more efficient, and make sure to remove code that's no longer needed. Fast update cycles are particularly important to keep users secure and safe from new types of attack as they happen. Enterprise customers can try out new versions of Chrome in Canary, Beta or Dev, and maintain control over software rollout to their staff. And if you're wondering about Chromebooks, well, the operating system they use, Chrome OS, works much the same way. If you're feeling adventurous, so you know, you want to try out features, early on, you can switch your Chromebook to a different Chrome OS channel. So that's how Chrome release channels work. If you want to find out more, take a look at the article here. And if you really love this stuff, there's even a blog about Chrome releases. You can keep track of the very latest versions of Chrome and actually view the code that got changed between versions. Anyway, thanks for watching and be sure to check out the other videos in the Chrome Concepts series. I'll see you in the next one. Bye.