HCaptcha should be compatible with the browser versions you mention in the task description, per https://docs.hcaptcha.com/faq/

Probably needs to be considered. AFAIK we said that we would not support browsers that had JS disabled, but have not considered that this unintentionally included all Grade C browsers.

IMO, if we decline this, we should make it very intentional that we no longer support Grade C browsers for any action other than reading the wiki. That should probably be done with broader consultation, because the browser compatibility we have AFAIK is a policy which has been hashed out already (so changing this without discussion appears to be a bad idea)

It gives that error as mentioned when you're logged as a normal user, but it works fine as user with skip-captcha permission in Firefox 57

Change #1283815 had a related patch set uploaded (by Mpostoronca; author: Mpostoronca):

[mediawiki/extensions/ConfirmEdit@master] Fix old browsers are unable to submit edit in Basic mode

https://gerrit.wikimedia.org/r/1283815

Chrome 63 or less don't get js served anymore https://gerrit.wikimedia.org/r/c/mediawiki/core/+/904851, can only fix for Chrome 64+
Ssee https://phabricator.wikimedia.org/T178356 when this change was implemented

Partial fix in https://phabricator.wikimedia.org/T425701

In T422222#11897535, @MPostoronca-WMF wrote:

Chrome 63 or less don't get js served anymore https://gerrit.wikimedia.org/r/c/mediawiki/core/+/904851, can only fix for Chrome 64+
See T178356 when this change was implemented

The change and task you refer to is about the Modern mode, which is an optional JS-based layer on top of Basic mode, limited to Grade A browsers. The bug report of this task, however, is about Basic mode. Basic mode is not impacted by T178356.

All pages start in Basic mode, including in modern browsers. See also:

• https://www.mediawiki.org/wiki/Compatibility#Browsers
• https://wikitech.wikimedia.org/wiki/MediaWiki_Engineering/Guides/Frontend_performance_practices#General_approach
• https://www.kryogenix.org/code/browser/everyonehasjs.html

Change #1288868 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/core@master] resourceloader: Add StandaloneModule for plain <script src> bundles

https://gerrit.wikimedia.org/r/1288868

Change #1288869 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Ship a Grade C captcha bundle via StandaloneModule

https://gerrit.wikimedia.org/r/1288869

Change #1289419 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] [WIP] hCaptcha: Ship a self-contained Grade C captcha bundle

https://gerrit.wikimedia.org/r/1289419

Change #1288869 abandoned by Kosta Harlan:

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Ship a Grade C captcha bundle via StandaloneModule

Reason:

Proposing to go with I1621589ffaa09d358571a602367f97b6ec225cd9 instead

https://gerrit.wikimedia.org/r/1288869

Change #1288868 abandoned by Kosta Harlan:

[mediawiki/core@master] resourceloader: Add StandaloneModule for plain <script src> bundles

Reason:

Proposing to go with I1621589ffaa09d358571a602367f97b6ec225cd9 instead

https://gerrit.wikimedia.org/r/1288868

@dom_walden desktop wikitext editor and Special:CreateAccount should usable now via a Grade C browser, can you please test this in your local environment, and/or verify it next week when the train is at group0? Thank you!

Change #1289419 merged by jenkins-bot:

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Ship a self-contained Grade C captcha bundle

https://gerrit.wikimedia.org/r/1289419

In T422222#11941348, @kostajh wrote:

@dom_walden desktop wikitext editor and Special:CreateAccount should usable now via a Grade C browser, can you please test this in your local environment, and/or verify it next week when the train is at group0? Thank you!

@kostajh I will keep updating this table. Browser/OS combinations not chosen very scientifically.

Testing locally (unless noted below):

- After submit: "Incorrect or missing CAPTCHA"
* After submit: "We're not quite finished loading the form..."
+ Before submit: "There was an error while loading the form..."
^ Not 100% reliable. Might have to reload page and try again.

(updated 2026-05-22 12:50:00 UTC)

In T422222#11944712, @dom_walden wrote:

In T422222#11941348, @kostajh wrote:

@dom_walden desktop wikitext editor and Special:CreateAccount should usable now via a Grade C browser, can you please test this in your local environment, and/or verify it next week when the train is at group0? Thank you!

@kostajh I will keep updating this table. Browser/OS combinations not chosen very scientifically.

Testing locally:

Browser	OS	Edit	Create account
Firefox 57	Windows 8	Working	Working
Firefox 51	Windows 10	Working	Working
Firefox 50	Windows 8.1	Not working-	Not working*
Firefox 49	Windows 10	Not working-
Firefox 49	Mac High Sierra	Not working-
Chrome 62	Windows 8.1	Working	Working
Chrome 51	Windows 10	Working	Working
Chrome 50	Windows 11	Not working+
Chrome 50	Mac Catalina	Not working+	Not working+
Chrome 49	Mac Mojave	Not working+

- After submit: "Incorrect or missing CAPTCHA"
* After submit: "We're not quite finished loading the form..."
+ Before submit: "There was an error while loading the form..."

Thanks, I'm going to make a follow up patch.

Change #1290793 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1290793

In T422222#11945255, @gerritbot wrote:

Change #1290793 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1290793

This should fix the Firefox 50 and 49 cases noted above; still working on Chrome 50 and 49.

Change #1290811 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid URL.searchParams in Grade C bundle

https://gerrit.wikimedia.org/r/1290811

In T422222#11945379, @gerritbot wrote:

Change #1290811 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid URL.searchParams in Grade C bundle

https://gerrit.wikimedia.org/r/1290811

This patch addresses compatibility with Chrome 49-50.

Change #1290793 merged by jenkins-bot:

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1290793

In T422222#11945319, @kostajh wrote:

In T422222#11945255, @gerritbot wrote:

Change #1290793 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1290793

This should fix the Firefox 50 and 49 cases noted above; still working on Chrome 50 and 49.

@kostajh Works for Firefox 50, but I still cannot get this to work for Firefox 49 . I see There was an error while loading the form.... Error in the console:

error.confirmedit Error: Unable to load hCaptcha script (retrying)
Stack trace:
loadHCaptcha/</onErrorCallback@http://blackbird:8080/w/load.php?modules=ext.confirmEdit.hCaptcha.gradeC&only=scripts&raw=1&version=12phd:144:967
load.php:140:764

None of the sha384 hashes in the integrity attribute match the content of the subresource.index.php
error.confirmedit Error: Unable to load hCaptcha script (retrying)
Stack trace:
loadHCaptcha/</onErrorCallback@http://blackbird:8080/w/load.php?modules=ext.confirmEdit.hCaptcha.gradeC&only=scripts&raw=1&version=12phd:144:967
load.php:140:764

error.confirmedit Error: Unable to load hCaptcha script (terminal)
Stack trace:
loadHCaptcha/</onErrorCallback@http://blackbird:8080/w/load.php?modules=ext.confirmEdit.hCaptcha.gradeC&only=scripts&raw=1&version=12phd:144:967
load.php:140:764

Change #1290811 merged by jenkins-bot:

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid URL.searchParams in Grade C bundle

https://gerrit.wikimedia.org/r/1290811

Change #1293661 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@wmf/1.47.0-wmf.3] hCaptcha: Ship a self-contained Grade C captcha bundle

https://gerrit.wikimedia.org/r/1293661

In T422222#11948345, @dom_walden wrote:

In T422222#11945319, @kostajh wrote:

In T422222#11945255, @gerritbot wrote:

Change #1290793 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@master] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1290793

This should fix the Firefox 50 and 49 cases noted above; still working on Chrome 50 and 49.

@kostajh Works for Firefox 50, but I still cannot get this to work for Firefox 49 . I see There was an error while loading the form.... Error in the console:

error.confirmedit Error: Unable to load hCaptcha script (retrying)
Stack trace:
loadHCaptcha/</onErrorCallback@http://blackbird:8080/w/load.php?modules=ext.confirmEdit.hCaptcha.gradeC&only=scripts&raw=1&version=12phd:144:967
load.php:140:764

None of the sha384 hashes in the integrity attribute match the content of the subresource.index.php
error.confirmedit Error: Unable to load hCaptcha script (retrying)
Stack trace:
loadHCaptcha/</onErrorCallback@http://blackbird:8080/w/load.php?modules=ext.confirmEdit.hCaptcha.gradeC&only=scripts&raw=1&version=12phd:144:967
load.php:140:764

error.confirmedit Error: Unable to load hCaptcha script (terminal)
Stack trace:
loadHCaptcha/</onErrorCallback@http://blackbird:8080/w/load.php?modules=ext.confirmEdit.hCaptcha.gradeC&only=scripts&raw=1&version=12phd:144:967
load.php:140:764

Thanks for letting me know. I've seen this too. This one might relate to peculiar issues with the networking set up between client / BrowserStack / WMF proxy, rather than grade C compatibility. Could you retry it on testwiki please?

Change #1293661 merged by jenkins-bot:

[mediawiki/extensions/ConfirmEdit@wmf/1.47.0-wmf.3] hCaptcha: Ship a self-contained Grade C captcha bundle

https://gerrit.wikimedia.org/r/1293661

Mentioned in SAL (#wikimedia-operations) [2026-05-26T09:26:06Z] <kharlan@deploy1003> Started scap sync-world: Backport for [[gerrit:1293661|hCaptcha: Ship a self-contained Grade C captcha bundle (T422222)]]

Mentioned in SAL (#wikimedia-operations) [2026-05-26T09:27:58Z] <kharlan@deploy1003> kharlan: Backport for [[gerrit:1293661|hCaptcha: Ship a self-contained Grade C captcha bundle (T422222)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.

Change #1293665 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@wmf/1.47.0-wmf.3] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1293665

Mentioned in SAL (#wikimedia-operations) [2026-05-26T09:32:58Z] <kharlan@deploy1003> Finished scap sync-world: Backport for [[gerrit:1293661|hCaptcha: Ship a self-contained Grade C captcha bundle (T422222)]] (duration: 06m 52s)

Change #1293665 merged by jenkins-bot:

[mediawiki/extensions/ConfirmEdit@wmf/1.47.0-wmf.3] hCaptcha: Avoid `for (const ... of ...)` in Grade C bundle

https://gerrit.wikimedia.org/r/1293665

Mentioned in SAL (#wikimedia-operations) [2026-05-26T09:44:01Z] <kharlan@deploy1003> Started scap sync-world: Backport for [[gerrit:1293665|hCaptcha: Avoid for (const ... of ...) in Grade C bundle (T422222)]]

Change #1293668 had a related patch set uploaded (by Kosta Harlan; author: Kosta Harlan):

[mediawiki/extensions/ConfirmEdit@wmf/1.47.0-wmf.3] hCaptcha: Avoid URL.searchParams in Grade C bundle

https://gerrit.wikimedia.org/r/1293668

Mentioned in SAL (#wikimedia-operations) [2026-05-26T09:45:53Z] <kharlan@deploy1003> kharlan: Backport for [[gerrit:1293665|hCaptcha: Avoid for (const ... of ...) in Grade C bundle (T422222)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.

Mentioned in SAL (#wikimedia-operations) [2026-05-26T09:52:08Z] <kharlan@deploy1003> Finished scap sync-world: Backport for [[gerrit:1293665|hCaptcha: Avoid for (const ... of ...) in Grade C bundle (T422222)]] (duration: 08m 07s)

Change #1293668 merged by jenkins-bot:

[mediawiki/extensions/ConfirmEdit@wmf/1.47.0-wmf.3] hCaptcha: Avoid URL.searchParams in Grade C bundle

https://gerrit.wikimedia.org/r/1293668

Mentioned in SAL (#wikimedia-operations) [2026-05-26T10:03:57Z] <kharlan@deploy1003> Started scap sync-world: Backport for [[gerrit:1293668|hCaptcha: Avoid URL.searchParams in Grade C bundle (T422222)]]

Mentioned in SAL (#wikimedia-operations) [2026-05-26T10:05:50Z] <kharlan@deploy1003> kharlan: Backport for [[gerrit:1293668|hCaptcha: Avoid URL.searchParams in Grade C bundle (T422222)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.

Mentioned in SAL (#wikimedia-operations) [2026-05-26T10:10:40Z] <kharlan@deploy1003> Finished scap sync-world: Backport for [[gerrit:1293668|hCaptcha: Avoid URL.searchParams in Grade C bundle (T422222)]] (duration: 06m 42s)

In T422222#11954208, @kostajh wrote:

Thanks for letting me know. I've seen this too. This one might relate to peculiar issues with the networking set up between client / BrowserStack / WMF proxy, rather than grade C compatibility. Could you retry it on testwiki please?

I have just tried on testwiki on browserstack and a local version of Firefox 49 and see the same errors.

In T422222#11954710, @dom_walden wrote:

In T422222#11954208, @kostajh wrote:

Thanks for letting me know. I've seen this too. This one might relate to peculiar issues with the networking set up between client / BrowserStack / WMF proxy, rather than grade C compatibility. Could you retry it on testwiki please?

I have just tried on testwiki on browserstack and a local version of Firefox 49 and see the same errors.

Did you have to override the security policy for Firefox 49 with regards to the SSL cert? If you visit each subdomain (e.g. assets-hcaptcha.wikimedia.org, hcaptcha.wikimedia.org, img-hcaptcha.wikimedia.org, etc) that you see in the network requests tab, and accept the security override, then it should work.

In T422222#11955035, @kostajh wrote:

Did you have to override the security policy for Firefox 49 with regards to the SSL cert? If you visit each subdomain (e.g. assets-hcaptcha.wikimedia.org, hcaptcha.wikimedia.org, img-hcaptcha.wikimedia.org, etc) that you see in the network requests tab, and accept the security override, then it should work.

Ah OK, it is working now. Thanks

Sorry, I let this slip off my radar. Testing just now on testwiki: