Intent to Deprecate: IE11 Support

[kristoferbaxter]

Summary

Microsoft has announced a final date for IE11 support: https://blogs.windows.com/windowsexperience/2021/05/19/the-future-of-internet-explorer-on-windows-10-is-in-microsoft-edge/

I'd like to propose we deprecate IE11 support on an aggressive schedule to coincide with the official timings from Microsoft.

Motivation

The AMP codebase contains a significant number of workarounds for compatibility with IE11, removing these workarounds nets a smaller and more performant library (as evidenced by our module/nomodule support today).

Dropping IE11 compatibility will allow the codebase to take advantage of more modern APIs in the CSS layer and JS layer without introducing additional testing pressure to ensure polyfills work for an increasingly out of date browser platform.

Additionally, there is a significant improvement to CI by removing IE11 support (estimated to be 18m+ per execution).

Impact on Existing Users

Existing users sometimes rely on AMP to handle IE11 compatibility issues, ensuring documents render as expected (minus custom CSS). This plan removes support, and as a result could introduce broken behaviour for IE11 users.

Alternative Implementation

Alternatively, we could continue to support IE11 in the nomodule codebase and exclude CSS rules that break rendering in IE11 or are unsupported.

Additional Context

1. This falls under the "Changes that affect fewer than 0.1% of crawler-accessible AMP pages" rule. Meaning no major revision bumps are required.
2. This has now passed the two week conversation timeline per rule "Allow at least 2 weeks of open discussion after the I2D is created before proceeding with the deprecation of the feature".
3. Discussion is now planned for the June 9th Design Review.
4. Pending approval from 3 approvers, this change will be announced on the mailing list and on Slack.
5. Following announcement the change will land in roughly 6 weeks to production.

Notifications

/cc @ampproject/wg-approvers

[nainar]

Let's do it!

[rsimha]

+1 to deprecating IE11 as soon as is feasible. Doing so will also help eliminate a large number of special case code paths in test and infrastructure code and simplify our CI workflows.

[jridgewell]

🎉💯🎊

[cramforce]

What data do we have to inform this decision?

[cramforce]

Also, CCing @ampproject/tsc

[davidstrauss]

The only counterpoint I think I can think of is to consider whether this affects any marginalized populations who, for any reason, have access to IE11 but not alternatives. I suspect that's not the case because I think IE11 is only available versions of Windows that are new enough to support alternatives as well. This was definitely a major issue for older IE versions, which remained in broad use (often without users having access or awareness of alternatives) well beyond Microsoft's support cycle.

If Edge is available everywhere IE11 is, though, I'm probably +1 on deprecation. Microsoft certainly isn't shy in letting users know about the alternative option of Edge if you use literally anything else, at least on Windows 10.

[dvoytenko]

I think Edge and Chrome both available everywhere where IE11 is. I roughly remember this was one of the reasons Edge switched to Blink. One of the major sources of holdovers might actually be enterprise-like users with the enterprise apps hardcoded to IE features and where a browser upgrade might be disabled by admins. This still might be a relatively important segment of userbase, however. For instance, it might include many libraries throughout the world.

That being said, if we go through our normal deprecation process, it should take us well past the official end-of-life published by Microsoft, which is June 2022.

[cramforce]

Another nail in the coffin is that Edge support "IE11 frame" where admins can designate certain domains to use MSHTML (legacy IE11 renderer) to render certain domains within Edge (so legacy apps that needs IE11 are not a problem). I've also heard that IE11 already opens Edge for certain domains by default where Microsoft determined that IE11 cannot render them (like youtube).

From Google's data (not specifically) for AMP there is definitely a major weekend/weekday swing in IE11 usage indicating the enterprise bias that Dima mentioned.

Overall usage is very low and sinking quickly.

I wonder if we have similar data for the AMP runtime.

[kristoferbaxter]

@jridgewell is working on getting data from cdn.ampproject.org which we can share.

[kristoferbaxter]

Percentage of Requests for AMP JavaScript Resources for IE11 from cdn.ampproject.org
Weekday – 0.001%
Weekend – 0.04%

[cramforce]

@kristoferbaxter Is this both AMP Cache and origin traffic? Could you break it out?

[kristoferbaxter]

This is both the Google AMP Cache and Origin traffic. We can split it out, but it will take a little bit.

[kristoferbaxter]

From @jridgewell here are some recent stats for Google AMP Cache and Origin traffic.

Day	Cache?	IE11
5/27/2021	FALSE	0.24%
	TRUE	0.03%
5/28/2021	FALSE	0.22%
	TRUE	0.04%
5/29/2021	FALSE	0.21%
	TRUE	0.02%
5/30/2021	FALSE	0.22%
	TRUE	0.06%
5/31/2021	FALSE	0.24%
	TRUE	0.03%
6/1/2021	FALSE	0.25%
	TRUE	0.07%
6/2/2021	FALSE	0.23%
	TRUE	0.02%
Grand Total	FALSE	0.23%
	TRUE	0.04%

[dvoytenko]

The higher percentage on non-cached pages make sense. The numbers are actually better (that is worse for IE) than I expected.

[jridgewell]

After design review, I approve this change.

[rsimha]

+1, approve.

[cramforce]

Approved ✅ 🎉

[davidstrauss]

I don't know if you need any more +1s, but here's mine!

[kristoferbaxter]

Fantastic, this is enough approvers and after enough time to make a public announcement and start work.

I'll kick this off today.

[kristoferbaxter]

Steps to complete:

• Messaging to developers via Slack announcement: https://amphtml.slack.com/archives/C0ADR0A0K/p1626277677017100
• Messaging to developers via Blog post: https://blog.amp.dev/2021/07/20/deprecation-of-internet-explorer-support/
• Messaging via console.log/info for impacted use-cases: ✨ Message announcing IE Deprecation #35240
• Removal of console.log/info ie deprecation/bugfix: remove isIe check #35833
• Official deprecation, code removal can happen at any point.

[dvoytenko]

+1

[vinayakkulkarni]

First vue, then Svelte.. Now everyone is deprecating IE!

Good days ahead for web devs

[niutech]

How about legacy Windows Phone devices, which have only Internet Explorer Mobile? I know they are unsupported, but still some people browse the Internet through them. Please don't break the web and at least provide basic backwards compatibility with IE, like static HTML with CSS and images, so that legacy users could see some content instead of White Screen Of Death.

[samouri]

How about legacy Windows Phone devices, which have only Internet Explorer Mobile? I know they are unsupported, but still some people browse the Internet through them. Please don't break the web and at least provide basic backwards compatibility with IE, like static HTML with CSS and images, so that legacy users could see some content instead of White Screen Of Death.

Previous to this I2D we were maintaining not perfect but not broken support for IE11. Given our recent stats that say < 0.23% of all page visits stem from IE11, we've decided to stop putting in effort to maintain support. While its likely much of the text/css/images of the pages will still render, most interactivity may break.

[cramforce]

But, FWIW, ideally this does not lead to White Screen Of Death. That should be true at least as long as the JS syntax we are serving can be parsed by IE11.

[jridgewell]

That should be true at least as long as the JS syntax we are serving can be parsed by IE11.

We also allow the <script amp-error> that will detect if there was a syntax error thrown by parsing v0.js, and will unhide the document. So, if we serve new syntax (or APIs) that IE11 can't handle, the document should be shown during the next event loop.

[jimmywarting]

+1 from me. Push the development forward!

Forcing developer to force users to upgrade browser will make other developers happy that it's gone and isn't forced to stick with something so old

[niutech]

@jimmywarting but not everybody can upgrade its browser. Think about legacy devices (such as Windows Phone) or out-of-date companies still sticking to IE. The web should be backwards compatible as much as it can, at least provide a readable fallback. You can go forward with innovations and provide a basic experience for legacy browsers.

[samouri]

Thank you all for the discussion.

We've already removed support for IE11 and completed all of the steps outlined here on Aug 26th.