Apple's latest milestone update to OS X, El Capitan--also known as version 10.11--was released to the general public Wednesday. It's a solid update that adds new features and makes a bunch of improvements without a whole lot of pain or drama, and after using a beta version all summer I think it's definitely ready for prime time.
Apple has shifted from its old approach of releasing software updates that strand old hardware on old versions of OS X. This probably has a lot to do with the pain of supporting security updates on old OS versions. Every Mac capable of running Mountain Lion -- released three years ago -- is capable of running El Capitan. Apple really, really wants most Macs built after about 2008 to run the latest version of the OS, which is now El Capitan.
In terms of compatibility, El Capitan will run on pretty much every MacBook model released since late 2008 (MacBook Pro models since mid 2007), all Mac minis since early 2009, all iMacs since mid-2007, all Mac Pros since early 2008, and the last (2009) model of Xserve. That's a whole lot of Macs, including models released as much as eight years ago. (2GB of memory and 8GB of available storage is required.)
To extend compatibility, Apple's new approach has been to drop support for individual features within the operating system, so if you run El Capitan on a late 2008 MacBook Air (for example), you can't use Handoff, Instant Hotspot, AirDrop, Metal, AirPlay Mirroring, or Power Nap. But you can still run the base operating system, including any security updates, and take advantage of some new features.
Users don't even have to upgrade a step at a time. Any version of OS X back to Snow Leopard (the 10.6.8 update is required) can update directly to El Capitan with no stops in between. The update is available for free as a download from the Mac App Store.
With that out of the way, here are the highlights of El Capitan:
Performance boosts. Apple has made a bunch of changes to improve Mac performance on existing hardware. Most notably, Metal, the graphics engine that Apple used to replace OpenGL on iOS 8 last year, has been added to OS X. (OpenGL is there for apps that demand it--and for older Macs that can't support Metal--but the focus has shifted.) In fact, Apple has updated many of OS X's key APIs, including Core Animation and Core Graphics, so that they now use Metal rather than OpenGL. The result, the company says, is major speed boosts in everthing from webpage rendering to PDF loading. And game developers should find boosted Mac graphics performance should they develop for metal--most likely by taking advantage of work they did to support Metal on iOS. Adobe has also committed to updating its Creative Cloud applications for Metal in the future.
More generally, Apple says that El Capitan launches and switches between apps faster, and it's updated the IMAP engine in the Mail application to be far more efficient in prioritizing what data it downloads, resulting in a more responsive interface, even over slow network connections such as airplane Wi-Fi.
Better bundled apps. Every OS X update usually brings with it updates to key bundled apps, and El Capitan is no exception. The Photos app, introduced this spring in an update to OS X Yosemite, reaches version 1.1 with the addition of batch geotagging and organizing features that were painfully absent from the original release. Photos 1.1 also supports third-party editing extensions, so outside developers can build editing tools that run inside the Photos interface.
Window management. In El Capitan, Apple has extended its full-screen mode to support two apps at once, a feature it's calling Split View. This is very much designed to look like the same feature that's available on some iPads with iOS 9, and it's also reminiscent of a similar feature in Windows. It's not a bad idea for smaller displays, though Mac users with big screens may find it a little pointless. To enter Split View, you click and hold on the green "stoplight" icon in a window's title bar, and then choose which side of the screen you'd like to use for that window. Then you need to click on another open window to select it as the counterpart. You can adjust the dividing line, so that one window is large and another is small. But essentially this is a tiling together of two apps in full-screen mode. As for me, I can already do this by resizing my own windows.
More impressive to me are the adjustments to Mission Control, the interface for finding windows as well as managing full-screen apps and multiple workspaces. Mission Control's been simplified and refined, fully displaying all of your open windows (previously it stacked all the windows from the same app, reducing its utility) and keeping them grouped geographically on your screen, so it's easier to find the window you're looking for.
Improved search and data sources. In El Capitan, Spotlight--Apple's systemwide search feature--has gotten quite an upgrade. You can now move it around the screen and resize it, query it with natural-language phrases like "PDFs created in September 2014," and use it to look up information from a much larger pool of Internet data sources (very much the same ones that Siri now supports on iOS 9). So you can get the latest Mets score by just typing "mets," or the latest San Francisco weather by typing "san francisco weather."
There's much more, of course, and Apple has detailed all the changes on its website. But in general, this is a solid update that shouldn't cause a whole lot of drama or consternation. It's free, compatible, not particularly surprising or jarring, and generally makes every Mac a little bit better. I'm happy to be running it, and I think most Mac users (at least, users of most Macs made in the last eight years) will think so, too.