> As a web dev, you want to use the latest ES/HTML/CSS specs [...]. How can you target modern users when the browsers on your 6-year old system isn't up-to-date

> As a web dev, you want to use the latest ES/HTML/CSS specs [...]. How can you target modern users when the browsers on your 6-year old system isn't up-to-date enough to render what most users will see? You can run latest browsers just fine. I'm talking to you now through Firefox Beta that was released a couple of days ago, on my 6 years old OS. It works just great, latest ES/HTML/CSS specs and all, same as yours. It's more up to date than my phone! However, if you're serious about testing, portability, accessibility, inclusion, quality, and just looking good to a worldwide audience for your site or app, then you won't rely on testing in a single browser on your own machine. Especially if your own machine is running the latest bleeding-edge version (as mine is). You may be using something like Selenium, BrowserStack, Sauce Labs etc. with a testing pipeline. Or (as I do), a bunch of browsers in cloud-based VMs. Even if it's just a manual testing pipeline, there are so many ways a complex web app can render or behave differently on different browsers it's not funny, so well worth testing complex things. Imagine trying to write something like a mini Google Sheets or Docs without testing on different browsers, while intending for it to be usable to a wide audience. It would break in more ways than you could imagine from testing only on the latest browser on your own machine. > Given that 97% of devices are on iOS 11 or later [...] I can't imagine why you care about those users. Not all apps are for consumers. And not all apps are for distribution on an app store. And some on a store are for particular audiences. For example government apps, financial services apps targetting people with little cash, and those running on fleets of purchased devices in a business (such as tablets) for a dedicated purpose. E.g. one of those I've dealt with was effectively a museum full of tablets fixed in place. Nodody's going to purchase new hardware in quantity if the old ones are working fine, just to please a developer who can't figure out how to built for an old target. (When I did that job, it wasn't iOS, but the same principle applies.) > A valid point as well - this is exactly the context in which COBOL is still used. I wonder if you're trying to suggest "really really old" with COBOL :-) The same maintenance issues apply to maintaining apps released just a couple of years ago, which supported 5 year old devices at the time they were released, and so aim to maintain the same until they have a major version change. (Especially business apps rolled out on a fleet of purchased devices, where continuity is a requirement. But also, consumer apps if you care about the customers.) > macOS developers exist, you know I do know, where do you think this thread came from :-) But the vast majority of shipped code is not open source, and when it is, most of it is used only on servers or inside devices.