In many ways, the lives of web developers have been getting easier these past few years. There are powerful tools that abstract away browser differences, allowing developers to use the latest technologies without worrying about older platforms. But the web has always been, and will continue to be, a messy place, and there is no way to abstract away the mess completely.
Which brings us to Safari. I am nowhere near the first person to say that Safari is the new IE, but consider this: Out of all of the major browsers (Firefox, Chrome, and let’s include Edge here for old time’s sake), Safari is the only one that is not an evergreen browser.
Safari is tied to Apple’s operating systems (macOS, iOS, and presumably the upcoming iPadOS) and Apple’s operating systems are tied to the hardware they support. We could afford to ignore these facts in the past, but circumstances are changing.
There was a time when most Mac users could upgrade their operating systems without a second thought; Mavericks, Yosemite, and El Capitan supported the same computers that ran Mountain Lion. As a result, web developers could assume most Mac users had access to the latest version of Safari.
This changed with Sierra of course. Apple has made separate upgrades for Safari available to older versions of macOS, but only up to a point (two major releases to be exact). Safari 11 is the last version available to users left on El Capitan, and if current trends continue, Safari 13 will be the last version available to users who cannot upgrade past High Sierra.
On the iOS side, unsupported devices hasn’t traditionally been seen as an issue. With most people upgrading their devices every 2-3 years and each model getting 4-5 years of software updates, iOS users are generally expected to be using the latest version at all times.
Industry watchers would be aware, though, that iPhone sales have been slowing down as part of a larger smartphone decline. Users are waiting longer to upgrade, opting to fix broken screens and failing batteries over wholesale replacements.
Perhaps there will be a near future where some people choose to use their “good enough” iPhones and iPads even after Apple has stopped supporting them. (As long as the apps they care about continue to work, what difference would an outdated operating system or web browser make?)
Should we strive to build sites that also work for these people using older versions of Safari? This is a decision for each individual developer or site owner, but this should be a conscious decision. “Last two versions” is a useful default for evergreen browsers, but Safari is not one of them.