Development branch shows blank page in Firefox 115.12.0esr

[bartvdbraak]

Steps to reproduce

1. Where are you starting? What can you see?

• Opening https://develop.element.io in Firefox ESR 115
  

2. What do you click?

• Nothing, the whole page is blank

Screencast_20240705_114613.webm

Outcome

What did you expect?

The application showing a login page or a guest view

What happened instead?

The application shows a blank page

Operating system

Debian GNU/Linux trixie trixie/sid x86_64, Linux 6.9.7-amd64, GNOME 44.9

Browser information

Firefox 115.12.0esr (Extended Support Release)

URL for webapp

develop.element.io

Application version

Commit b4d3430

Homeserver

No response

Will you send logs?

Yes

[t3chguy]

See https://github.com/element-hq/element-web#supported-environments

Last 2 major versions of Chrome, Firefox, and Edge on desktop OSes

That would be Firefox 126 & 127. Intl.Segmenter needs Firefox 125 minimum https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Segmenter

[seangenabe]

Just showing a blank page without any error message is toxic and not user-friendly. At least show a message that the user's browser is not supported.

[t3chguy]

@seangenabe yup: #27677

[konomikitten]

Debian Stable only ships with Firefox ESR, there's probably a bunch of corporations who also use Firefox ESR. Surely a browser that's still being updated should be supported?

[t3chguy]

Delaying features by ~42 weeks that ESR claims to update every would not really be an option. We never claimed support for ESR and it working was entirely incidental by virtue of us using feature detection rather than browser listing

[wodny]

And here is a thread after it deployed to production - #27682 and a request to support Firefox ESR - #27684.