#3759 f24ce99 Thanks @MilesChou! - Fixes an issue where monolingual sites using a region-specific locale (e.g., zh-TW) as the default would incorrectly display base language translations (e.g., zh Simplified Chinese) instead of the region-specific ones (e.g., zh-TW Traditional Chinese).

#3768 a4c6c20 Thanks @delucis! - Improves performance of sidebar generation for sites with very large sidebars

#3644 0d2e7ed Thanks @HiDeoo! - Adds support for Astro v6, drops support for Astro v5.

Upgrade Astro and dependencies

⚠️ BREAKING CHANGE: Astro v5 is no longer supported. Make sure you update Astro and any other official integrations at the same time as updating Starlight:

npx @astrojs/upgrade

Community Starlight plugins and Astro integrations may also need to be manually updated to work with Astro v6. If you encounter any issues, please reach out to the plugin or integration author to see if it is a known issue or if an updated version is being worked on.

Update your collections

⚠️ BREAKING CHANGE: Drops support for content collections backwards compatibility.

In Astro 5.x, projects could delay upgrading to the new Content Layer API introduced for content collections because of some existing automatic backwards compatibility that was not previously behind a flag. This meant that it was possible to upgrade from Astro 4 to Astro 5 without updating your content collections, even if you had not enabled the legacy.collections flag. Projects would continue to build, and no errors or warnings would be displayed.

Astro v6.0 now removes this automatic legacy content collections support, along with the legacy.collections flag.

If you experience content collections errors after updating to v6, check your project for any removed legacy features that may need updating to the Content Layer API. See the Starlight v0.30.0 upgrade guide for detailed instructions on upgrading legacy collections to the new Content Layer API.

If you are unable to make any changes to your collections at this time, including Starlight's default docs and i18n collections, you can enable the legacy.collectionsBackwardsCompat flag to upgrade to v6 without updating your collections. This temporary flag preserves some legacy v4 content collections features, and will allow you to keep your collections in their current state until the legacy flag is no longer supported.

#3704 375edcc Thanks @florian-lefebvre! - Fixes autocomplete for components exported from @astrojs/starlight/components/*

⚠️ Potentially breaking change: This change moves some files used in Starlight’s component internals out of the components/ directory. Direct use of these files was not and is not officially supported. If you previously imported TableOfContents/starlight-toc.ts, TableOfContents/TableOfContentsList.astro, Icons.ts, or SidebarPersistState.ts, please review your code when updating.

#3729 3642625 Thanks @delucis! - Improves Starlight’s default body font stack to better support languages such as Chinese, Japanese, and Korean on Windows.
For most users there should be no visible change.

If you would prefer to keep the previous font stack, you can add the following custom CSS to your site:

:root {
  --sl-font-system: ui-sans-serif, system-ui, 'Segoe UI', Roboto,
    'Helvetica Neue', Arial, 'Noto Sans', sans-serif, 'Apple Color Emoji',
    'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji';
}

#3598 fff38d5 Thanks @HiDeoo! - Makes hover styles consistent in Starlight’s navigation bar

Previously, the social icon links and language/theme switchers in Starlight’s navigation bar, dimmed on hover.
After this change, they now increase in contrast on hover instead.
This matches hover behavior elsewhere, for example in the sidebar, table of contents, or search button.

⚠️ Potentially breaking change: this is a subtle change to the hover style colors.
If you want to preserve the previous styling, you can add the following custom CSS to your site:

starlight-theme-select label,
starlight-lang-select label {
  color: var(--sl-color-gray-1);

  &:hover {
    color: var(--sl-color-white);
  }
}

.social-icons a:hover {
  color: var(--sl-color-text-accent);
  opacity: 0.66;
}

#3644 0d2e7ed Thanks @HiDeoo! - ⚠️ BREAKING CHANGE: The minimum supported version of Starlight is now 0.38.0

Please use the @astrojs/upgrade command to upgrade your project:

npx @astrojs/upgrade

#3644 0d2e7ed Thanks @HiDeoo! - ⚠️ BREAKING CHANGE: The minimum supported version of Starlight is now 0.38.0

Please use the @astrojs/upgrade command to upgrade your project:

npx @astrojs/upgrade

#3644 0d2e7ed Thanks @HiDeoo! - ⚠️ BREAKING CHANGE: The minimum supported version of Starlight is now 0.38.0

Please use the @astrojs/upgrade command to upgrade your project:

npx @astrojs/upgrade

#3534 703fab0 Thanks @HiDeoo! - Fixes support for running builds when npx is unavailable.

Previously, Starlight would spawn a process to run the Pagefind search indexing binary using npx. On platforms where npx isn’t available, this could cause issues. Starlight now runs Pagefind using its Node.js API to avoid a separate process. As a side effect, you may notice that logging during builds is now less verbose.

#3656 a0e6368 Thanks @delucis! - Fixes several edge cases in highlighting the current page heading in Starlight’s table of contents

#3663 00cbf00 Thanks @lines-of-codes! - Adds Thai language support

#3658 ac79329 Thanks @delucis! - Avoids adding redundant aria-current="false" attributes to sidebar entries

#3382 db295c2 Thanks @trueberryless! - Fixes an issue where the mobile table of contents is unable to find the first heading when a page has a tall banner.