Upgrade to Analytics.js 2.0

Analytics.js 2.0 is fully backward compatible with Analytics.js Classic when you use the default Segment snippet in a standard implementation. To upgrade your sources, follow the manual upgrade steps below, or see the schedule for automatic migration. As with all upgrades, Segment recommends that you start development on a non-production source to test the upgrade process and outcome, prior to upgrading your production sources.

Deprecation of Analytics.js Classic

Segment ended support and maintenance for Analytics.js Classic on August 31, 2022. On February 28, 2023, Segment will remove access to Analytics.js Classic.

Upgrade to Analytics.js 2.0 before access ends for Analytics.js Classic. See the Analytics.js 2.0 docs to learn more about the new source.

Manual upgrade

To upgrade a source to Analytics.js 2.0:

  1. In your Segment workspace, open the Connections page.
  2. Open the JavaScript source you will upgrade.
  3. On the Settings tab, open the Analytics.js category.
  4. Enable the flag for Analytics 2.0.
  5. Within 5 minutes, the source receives Analytics.js 2.0. No code or tag changes required.
  6. Open the Debugger to ensure that events are flowing as expected.

If you set 'Segment.io:' false in the integrations object, Analytics.js 2.0 drops the event before it reaches the Source Debugger.

Automatic migration

Analytics.js sources will upgrade to Analytics.js 2.0 on the date below, according to the account tier. On the date listed, Segment will upgrade all Analytics.js sources within the associated account tier.

Segment Plan Upgrade Date
Free June 15, 2021
Team July 6, 2021
Business* June 2022

*If you’re on a business plan, please reach out to friends@segment.com to see if your account is part of the upgrade in June 2022.

The plans and dates listed above are subject to change.

Revert to Analytics.js Classic

Once a source moves to Analytics.js 2.0, you can follow the steps above in Manual migration to roll back to Analytics.js Classic.

Cases that require additional intervention

In some cases, upgrading to Analytics.js 2.0 requires manual effort beyond enabling the Analytics.js 2.0 toggle.

Using in-domain instrumentation CDN aliasing

If the source you intend to upgrade uses the in-domain instrumentation as well as a custom “Alias for analytics.js”, then you should update the Analytics.js snippet to the latest version (4.15.3 or higher) before you toggle on Analytics.js 2.0.

Using a mix of Analytics.js Classic and 2.0 sources

If you’re using a mix of Analytics.js Classic and 2.0 sources, the classic source won’t be able to use the anonymous ID set by Analytics.js 2.0. In order to fix this, update all sources to 2.0.

Analytics.js 2.0 removes inbuilt quotes from cookie values, resulting in a different format for the ajs_anonymous_id value when compared to Analytics.js Classic. Though you can retrieve cookie values with standard supported functions, you’ll need to configure your environment to accept the new format if your implementation relies on accessing the cookie value directly.

If you configured different sources for different subdomains of your website, switch them to Analytics 2.0 at the same time. Switching them at the same time ensures that subdomain tracking won’t break. In cases when you need to gradually update to Analytics 2.0, the utility plugin can help match the ajs_anonymous_id cookie format and ensure that users are consistently identified across your subdomains.

Using a strict content security policy on the page

Analytics.js 2.0 asynchronously loads different pieces of the library as needed. If the source you’re upgrading uses a strict Content Security Policy (CSP) that allows JavaScript to be downloaded from specific locations, then you need to update the CSP to account for all the pieces used for Analytics.js 2.0. Therefore, beyond allowing the main analytics.min.js script, you should allow the following paths in your CSP:

  • https://cdn.segment.com/v1/projects/<WRITE_KEY>/settings
  • https://cdn.segment.com/analytics-next/bundles/*
  • https://cdn.segment.com/next-integrations/integrations/*

Previously, it was possible to attach trackLink to any element, and a trackLink call would fire for that element if it wasn’t a link. Now, when you attach trackLink to a non-link element, an additional search of that element’s children occurs for any nested links and fires track calls based on those links. If you wish to fire track calls on non-link elements that have links as children, you can use a track call instead.


I’m already using Analytics 2.0, why am I still receiving the message to upgrade?

It’s possible that a different source you’re using is still leveraging an older version of Analytics.js. A way to see which sources are on which versions is to go to the source overview page, then filter on the Analytics.js version.

It’s also possible that you have used a write key from another source type (like Ruby) to instrument your JavaScript source. To upgrade these sources, you may need to create a new JavaScript source and replace the write key.

Should I expect any glitches or downtime when switching to Analytics 2.0?

Segment expects no downtime or glitches when switching to A.js 2.0.

How can I validate that my source is using Analytics.js 2.0?

If you’re using A.js 2.0, the library field will look like the code snippet below ( next will be part of the version field):

"library": {
      "name": "analytics.js",
      "version": "next-1.XX.X"

Are there specific things to test from an engineering point of view?

Like any software upgrade, Segment advises you to start with one source, or a development or staging source. Then you should ensure that traffic is flowing the way you expect it to and that it goes to the appropriate destinations.

What happens if I don’t upgrade by the end of service date?

There will not be any changes to your sources on the end of service date. However, if you encounter issues or need support, the support team will advise you to upgrade to 2.0. All new features will only be available on the 2.0 versions.

This page was last modified: 30 Aug 2022

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