Mattermost is considering dropping support for Internet Explorer (IE11)

Questions to our Community

We are primarily looking for feedback from the Mattermost community on the potential impact of dropping support for IE11.

Would you be impacted? If so, would you be able to migrate to the Mattermost Desktop Apps or another web browser? If not, what would block your migration?

Any and all feedback is highly appreciated! To learn more about why we’re considering removing support, see below:

Background on Internet Explorer (IE).

Mattermost supports a number of browsers, including recent versions of:

  • Firefox
  • Chrome
  • Safari
  • Edge
  • IE

Unlike the other browsers, IE is no longer under active development and has been replaced by Edge on Windows. This means that, over time, maintaining compatibility with IE presents a disproportionate burden on the development team as, unlike other browsers, it is no longer keeping pace with evolving web standards. However, some large enterprises still use IE internally, which is the reason we have continued to support it up until now.

Why are we considering dropping IE support?

As web standards continue to evolve, other browsers keep pace with these changes, but IE, as it is unmaintained, does not. This means we have an increasing volume of brittle, special-case code in the webapp to maintain compatibility with IE. This special-case code receives no usage from the core team, and requires its own QA testing. We have reached the point where, to continue the improvement and forward progress of the web app, it is necessary to make use of technologies which are not supported (and never will be supported) by IE.

For specific examples of areas currently hindering development, see

Moreover, below is a list of deprecations in the wider world:

  1. IE is a legacy browser. Although Microsoft will continue to support it until Windows 10 EOL, it is deprecated in favor of Microsoft Edge.
  2. Microsoft considers that it should only be used “for compatibility with legacy intranet systems” and, wherever possible, a modern browser such as Edge should be used for all other Intranet/Internet resources.
  3. Slack will be ending IE support from 15th March 2019.

Alternatives for communities currently using Mattermost with IE.

Mattermost offers a fully functional desktop application, which can be rolled out by enterprises where using an alternative web browser to access Mattermost is not an option. To assist an organization with a wide deployment of the desktop application, an MSI for Windows has been released as Alpha with step-by-step docs on installation and setting group policies.



First: Edge will also change soon the Engine to Chromium. But it will also include the IE Engine for legacy. If older Windows will get the new Edge is i guess not yet clear.

For the IE11 Drop:

IE11 will stay on Systems with LTSB/LTSC Windows or Server until 2028.

In my opinion Mattermost missed the right time for a drop. With the new ESR 5.9 there was a perfect timing.

I would consider dropping after a new ESR, as you give then your customers the choice what to do. Because when you drop it on a non ESR Version, customers with IE needs are in a unpleasant situation.

Thanks @JtheBAB for the reply!

Do you mean that ESR 5.9 shouldn’t have supported IE11 anymore, or that it should for customers who use IE11?

5.9 ESR must support IE11. And as there is already 5.10 out you may drop IE11 only with the next ESR version.

Got it, thank you! We’ll take this into consideration.

Continuing IE support is blocking the rollout of infinite scroll, making Mattermost feel old and clunky. There are plenty of options available, including the desktop app, so continuing to support a browser that’s only hanging around for legacy systems is backwards thinking.

I can’t imagine any company disallows non-IE browsers these days as so much of the Internet is broken by it. Literally the only reason people still use it, as mentioned above, is for legacy systems that will never be updated to work with anything else.

Drop it, drop it, drop it!

1 Like

I couldn’t be more in favor of ditching IE11.
As pointed out, outside of some very specific cases, such as usage in old, legacy systems, there is no reason a “normal” person would use IE.
Supporting IE makes development of pretty much any web app a pain, slowing it down considerably. Stuff that just works in any normal browser for years now, often just doesn’t in IE. I am not a developer per se, but I happen to work with some web layouts from time to time, and at one point I just changed my approach and started ignoring IE (or rather throwing an error message about lack of support), because it is simply not worth it.
Please, just ditch it.
Thank you.