Unsupported browser error on latest Element web

[Chiaki]

Steps to reproduce

1. Where are you starting? What can you see?
   When I'm trying to open Element web, I got an error: Unsupported browser - Your browser can't run Element.
2. What do you click?
   https://app.element.io/

Outcome

What did you expect?

A working Element web client.

What happened instead?

A notice about unsupported browser.

Operating system

Windows

Browser information

Latest Firefox ESR, latest Firefox

URL for webapp

app.element.io

Application version

No response

Homeserver

No response

Will you send logs?

No

[t3chguy]

Will you send logs?
No

Without logs there is nothing to investigate here and this issue would need to be closed

[Chiaki]

Will you send logs?
No

Without logs there is nothing to investigate here and this issue would need to be closed

Ok. But what kind of logs you will need? Browser console logs or what?

[t3chguy]

Yes, Element runs entirely in your browser, those are the only logs which relate to the application

[Chiaki]

Yes, Element runs entirely in your browser, those are the only logs which relate to the application

I know, but I can see only an error page. Web client is not even "starting".
This is what I have in browser console output:

Browser missing feature: 'regexpunicodesets'
Browser missing feature: 'intlsegmenter'
TypeError: Intl.Segmenter is not a constructor

If this helps.

[t3chguy]

Sounds like your browser is missing the features required to run. Both of those features are available in Firefox ESR 128.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Segmenter#browser_compatibility added in added in 125
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicodeSets#browser_compatibility added in 116

[Chiaki]

Sounds like your browser is missing the features required to run. Both of those features are available in Firefox ESR 128.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Segmenter#browser_compatibility added in added in 125 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicodeSets#browser_compatibility added in 116

I see. Latest version of ESR is 115.13 at this moment (https://whattrainisitnow.com/release/?version=esr).
So this is probably a bit early update for all users, because Mozilla is not pushed update to the new branch yet global.

[t3chguy]

Latest ESR is 128. 115 is the old ESR which Mozilla is still supporting until October, and we have not yet ever shipped a release which claimed ESR compatibility. See https://github.com/element-hq/element-web/tree/master?tab=readme-ov-file#supported-environments for the environments we claim to support for the version which you are using.

The next release will widen compatibility somewhat but ESR 115 (with a featureset 14 months old) will only be partially supported.