Zendesk Templating API v4 migration: the Copenhagen theme deadline

If your Help Center theme is older than Copenhagen 4, it runs on an old Templating API. Zendesk will stop accepting those themes and then upgrade the rest. This guide covers what that means for a custom theme.

The end-of-life timeline

These dates come from Zendesk's announcement, checked on October 1, 2026.

September 14, 2026

Importing v1, v2 and v3 themes is blocked for new accounts.

November 25, 2026

Zendesk releases a command-line (ZCLI) upgrade tool for custom-coded themes.

March 1, 2027

An in-product upgrade tool arrives. Importing v1, v2 and v3 themes is blocked for all accounts.

July 31, 2027

Remaining legacy themes are upgraded to v4 by Zendesk, and v1 to v3 are removed.

The practical deadline is July 31, 2027. Before that, imports of old themes stop working, so you cannot restore a backup or move a theme to a new account.

How to check your theme version

1. In Guide, open Customize design.
2. On your live theme, choose Customize, then Edit code.
3. Open manifest.json and find api_version.

A value of 4 means you are done. A value of 1, 2 or 3 means the theme needs to move. Check every theme in the list, not only the live one.

What breaks on a custom theme

Zendesk's own v3 to v4 upgrade notes list the changes. These are the ones that hit custom themes:

• The new request page loses {{request_form}} and {{follow_up}}. You build the form from {{new_request_form}}, and Copenhagen renders it with a React component.
• The document head needs new script blocks, and the theme needs Copenhagen's assets folder.
• On the home page, sections no longer carry articles, articles_count or more_articles.
• Lists are capped: 5 sections and 5 child sections per category, and 5 articles per child section. Outside the article page, an article has no body or vote. It has a snippet instead.

A theme that has never touched these areas can be quick to move. A heavily forked one rarely is, because the request form is where most custom code lives.

A short migration checklist

1. List your themes and note each api_version.
2. Export a copy of every theme you plan to keep.
3. Diff your theme against the current Copenhagen release, so you know which files you changed.
4. Set api_version to 4 and copy in Copenhagen's assets folder.
5. Rebuild the new request page and the document head from Copenhagen, then re-apply your changes on top.
6. Fix home page code that read section articles.
7. Test as a visitor and as a signed-in user: search, an article, the request form with attachments, and the request list.
8. Publish, and keep the old copy until you are sure.

If you bought a theme from a vendor, ask them whether it is on v4. The announcement tells Marketplace theme owners to check this with their vendor.

Questions about your theme? Write to hello@zenthemelab.com. Not affiliated with Zendesk.