[RFC] Dropping support for older browsers

[Sam Clegg]

We are currently considering a change to bump our minium browser version support: https://github.com/emscripten-core/emscripten/pull/26677

The minimum supported versions would change as follows:

chrome: 74 -> 85
firefox: 68 -> 79
safari: 12.2 -> 14.0

I think the Safari bump is the only one that might be controversial.  Are there any folks out there still targeting browsers this old?

cheers,

sam

[Brooke Vibber]

This should be fine for Wikipedia's back-compat codec shim; we have alternate fallbacks for affected content on old devices that fall out of emscripten support if we update the shim (we expected older Safaris to fall out of our general JavaScript support anyway!).

-- brooke

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[Sam Clegg]

On Tue, Apr 14, 2026 at 1:15 PM Brooke Vibber <br...@pobox.com> wrote:

This should be fine for Wikipedia's back-compat codec shim; we have alternate fallbacks for affected content on old devices that fall out of emscripten support if we update the shim (we expected older Safaris to fall out of our general JavaScript support anyway!).

Thanks brooke, thats good to know.    I imagine you have one of the most back-compat-demanding content sets out there.   BTW, are you able to share what is your current old-supported-safari version?

cheers,

sam

 

-- brooke

On Tue, Apr 14, 2026 at 9:41 AM 'Sam Clegg' via emscripten-discuss <emscripte...@googlegroups.com> wrote:

We are currently considering a change to bump our minium browser version support: https://github.com/emscripten-core/emscripten/pull/26677

The minimum supported versions would change as follows:

chrome: 74 -> 85
firefox: 68 -> 79
safari: 12.2 -> 14.0

I think the Safari bump is the only one that might be controversial.  Are there any folks out there still targeting browsers this old?

cheers,

sam

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[Brooke Vibber]

On Tue, Apr 14, 2026 at 2:08 PM 'Sam Clegg' via emscripten-discuss <emscripte...@googlegroups.com> wrote:

On Tue, Apr 14, 2026 at 1:15 PM Brooke Vibber <br...@pobox.com> wrote:

This should be fine for Wikipedia's back-compat codec shim; we have alternate fallbacks for affected content on old devices that fall out of emscripten support if we update the shim (we expected older Safaris to fall out of our general JavaScript support anyway!).

Thanks brooke, thats good to know.    I imagine you have one of the most back-compat-demanding content sets out there.   BTW, are you able to share what is your current old-supported-safari version?

Wikipedia's general JavaScript support matrix is pretty conservative, with primary target the baseline for ES2017 (with specific things occasionally requiring specific newer browsers as progressive enhancement) and intending for basic site functionality to work on modern browsers even with JS off, and older browsers back to some level where CSS and markup stop behaving nicely.

IIRC our primary support limit is Safari 11 or so -- but we've been pretty aggressive about dropping enhancement features on anything older than about Safari 15 if *anything* is tricky to work around, and not even testing below 12 on most feature work I've touched lately. (I think we're going to update this matrix soon.)

https://www.mediawiki.org/wiki/Compatibility#Browser_support_matrix

The WebAssembly codec shim (ogv.js) was created in the period before Apple adopted VP8/VP9/AV1 codec support, since for *waves hands at a still ongoing war between two groups of megacorps* complex patent licensing reasons our weird open-source project has avoided adopting H.264, the most common video codec. :) Until we get our licensing situation worked out (and it's getting ugly again with some lawsuits targeting AV1 users now), we continue using the weird Google-backed open codecs and patent-expired formats.

At this point modern Macs and iPhones (iOS 17.4 and later) understand our WebM VP9 video just fine natively, so the shim is targeting a smaller slice of legacy devices and I expect the video player UI itself to require a newer iOS sooner or later anyway so iOS 11-13 is likely to get end-of-lifed for practical reasons of updating dependencies before we recompile the shim with a newer emscripten. :)

To ensure that we have a video fallback on legacy devices as the JavaScript frontend moves on, we've added a really blurry low-resolution Motion JPEG fallback that works across all legacy iOS/iPadOS devices, with or without the JavaScript player frontend. If we ever get our licensing issues worked out, the fallback would likely become regular old H.264 which will be a lot less blurry.

Currently we're not using emscripten for anything else in Wikipedia's UI but there's a large class of fun Interactive-Things-Brought-Into-The-Browser that I hope to use it for on a future content-focused project. :)

-- brooke