Slack officially supports Chrome. Access to Chromium may be disabled in the future.

Chromium is the open source version of Google's Chrome web browser. It's literally Chrome, without various proprietary extensions. It's also the standard Chrome on Linux — it's in every distro.

We use Slack at work as a sort of outsourced IRC. A few days ago, I got this message:

This browser is no longer supported
We know it’s a hassle to change browsers, but we want your experience of Slack to be fast, secure, and the best it can possibly be. To continue using Slack, please switch to one of our supported browsers by March 15. As always, feel free to contact us if you have any questions.

So I contacted Support about this nonsensical error:

Browser check told me Chromium 76 was too old

warning that my browser was outdated: "This browser is no longer supported
We know it’s a hassle to change browsers, but we want your experience of Slack to be fast, secure, and the best it can possibly be. To continue using Slack, please switch to one of our supported browsers by March 15. As always, feel free to contact us if you have any questions."

It's Chromium - Version 76.0.3809.100 (Official Build) Built on Ubuntu , running on Ubuntu 18.04 (64-bit)

user agent is: "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/76.0.3809.100 Chrome/76.0.3809.100 Safari/537.36"

is Slack seriously unable to support Chromium, the standard on Linux?

They replied:

Thanks for getting in touch today. Just to make sure I'm understanding correctly, are you using a browser that embeds Chromium, such as Opera, Franz, Rambox, etc.? If so, I'm afraid we don't currently support these, even if they are implementing an up to date version of Chromium. At this time we support Google Chrome, Firefox, Safari, and Microsoft Edge. This article contains more details in case you'd like to take a peek: https://get.slack.help/hc/en-us/articles/115002037526-Minimum-requirements-for-using-Slack.

If you are using a supported browser, can you please let me know if this warning is a small pop up in the corner of your screen, or if it's fully blocking your use of Slack?

I clarified:

It's literally just Chromium - not an embed, but actual Chromium. Ubuntu 18.04, from the repos - they update it whenever there's a new version from Google.

So far it's not blocking anything, but it's telling me this up-to-date browser is out of date.

So, do you support up-to-date Chromium? I reiterate, this is the standard Chrome in Linux.

And, in reply:

Apologies for the delay in getting back to you here — just wanted to check in with some teammates to double check that I have the right info. Unfortunately we do not support Chromium, and only support the four web browsers I mentioned in my previous message. I have shared your feedback that you'd find it helpful for us to offer support for this, but I'm afraid I don't have any info on if or when that may be.

Sorry for the disappointing news here, but if I can lend a hand with anything else for now just let me know.

That's official confirmation from Slack that Chromium is an UNSUPPORTED BROWSER on Linux that may STOP WORKING SOON, they only support Chrome.

Evidently, Slack is doing user-agent testing on browsers, and, at some point, is likely to start blocking ones not on the whitelist.

Even though Slack's packaged desktop app version is built on Electron — which is literally Chromium, wrapped up in a little bundle.

So ... I wouldn't go expecting competence from Slack, if I were you.

(Can't wait till Slack requires an official DRMed Windows binary with ads, that detects and blocks Wine. Or something.)

Update: and Slack is now actively blocking Chromium from working! Great going guys, clearly you're competent developers who have any idea what you're doing. User-agent switching works so far.