2026 Optimizely CMS 12 (PaaS) release notes

Follow this article to receive email notifications when new packages are available for Optimizely Content Management System (PaaS) products. Product packages are found on the Optimizely NuGet server and include the following products:

• Optimizely Content Management System (CMS 12)
• Content Delivery API
• Optimizely Forms
• Optimizely Language Manager
• Optimizely Reporting

Most recent releases

CMS 12

EPiServer.CMS.Core

12.23.1—January 22, 2026

• Bug fixes
  • CMS-47283 – Fixed an issue where link validation warnings for XhtmlString properties were incorrectly displayed across all language versions of a content item, even when a broken link was present in only one specific language version.

EPiServer.CMS.UI

12.34.2—January 23, 2026

• Enhancement
  • Added a tooltip feature in CMS 12 that displays the names of active servers for each URL.

• Bug fixes

  • CMS-47914 – Fixed an issue where the ReadOnlyMiddleware was incorrectly redirecting health check endpoints, causing them to fail, particularly in failover applications. The health check path is now whitelisted in the middleware request validator to ensure proper functionality.
  • CMS-47408 – Fixed an issue where a binary-breaking change in EPiServer.Cms.Shell.IContentExtensions.PreviewUrl prevented third-party plugins and add-ons from functioning correctly after upgrading EPiServer.Cms.Shell.UI from versions 12.20.0.0 to 12.33.5.0. This change, caused by the addition of an optional parameter, was addressed to restore compatibility.
  • CMS-47134 – Fixed an issue where users could set their new password to their current password in the MySettings section, which was incorrectly accepted. The system now correctly displays a validation error, preventing the new password from being identical to the current one.
  • CMS-46675 – Fixed an issue where you could not hide the AllowedTypes description (and now you can), providing you with more control over content type configurations.
  • CMS-45964 – Fixed an issue where, when selecting content via a search component within a modal dialog for a ContentArea limited to a single content type (such as ImageData), clicking a search result would close the dialog without adding the selected content item to the ContentArea. Now, the selected content is correctly added.
  • CMS-45741 – Fixed an issue where updating the content of a personalized inline block within a ContentArea could inadvertently overwrite the content of other personalized inline blocks in the same ContentArea. This fix ensures that changes to one inline block are isolated and do not affect others.
  • CMS-43553 – Fixed an issue where the CMS UI's right panel or main content area would sometimes fail to stretch to full width, especially when opening multiple tabs rapidly. The layout now consistently maintains its intended full-width display.
  • CMS-39989 – Fixed an issue where the old domain world.episerver.com was hardcoded in the UI for the feedback link and RSS Data fetcher, causing potential domain redirection problems. The domain was updated to world.optimizely.com.

  Content Delivery API

  EPiServer.ContentDeliveryApi

  3.12.6—January 28, 2026

  • Bug fix
    • HAPI-2931 –Added support for Content Management API (CMA) to create content with any valid language codes, removing the previous restriction to OS-supported cultures. This allows for the creation of content in languages such as zh-CN (Chinese simplified) directly through CMA, even if not listed in CultureInfo.GetCultures().

  3.12.5—January 20, 2026

  • Bug fix
    • HAPI-2924 – Fixed an issue where special characters in the “Remaining URL” field of a LinkItem were not correctly encoded when returned by the Content Delivery API and Optimizely Graph.

  Optimizely Forms

  Optimizely.CMS.Forms.*

  1.5.0—March 13, 2026

  • Enhancement
    • Added smooth deployment support for Optimizely Forms with Optimizely Graph. Form data is now preserved during Optimizely Graph index rebuilds, preventing data loss and ensuring forms continue to function as expected after activating smooth deployment.

  1.4.2—January 5, 2026

  • Bug fixes
    • AFORM-4730 – Fixed an issue where the delta synchronization job would fail when content was deleted, preventing users from successfully indexing content. The delta indexing job now runs as expected, ensuring content can be indexed without errors even after deletions.
    • AFORM-4733 – Fixed an issue where the Optimizely.Cms.Forms.ContentGraph package was incorrectly attempting to index non-Form content, leading to an ArgumentException and indexing failures for regular content (pages, blocks, and folders). The Forms ContentGraph package now correctly processes only Form-related content, ensuring smooth indexing for all content types.
    • AFORM-4734 – Fixed an issue where a NullReferenceException would occur during site initialization when EPiServer.Forms, Optimizely.Cms.Forms.ContentGraph, and Optimizely.ContentGraph.Cms packages were present, preventing the site from starting. Sites now initialize successfully with these packages installed.

  Optimizely Language Manager

  EPiServer.Labs.LanguageManager

  5.5.3—January 5, 2026

  • Bug fix
    • LM-714 – Fixed an issue where the Learning Management (LM) system was using an outdated version (0.21.1) of the axios package, which contained a known vulnerability. Language Manager was upgraded to use axios version 0.22.0, aligning with the version used by CMS, to eliminate this security risk.

  Optimizely Reporting

  February 03

  • Enhancement
    • Improved insights into the Crawl-to-Refer Ratio with new comparison capabilities. You can view the crawl-to-refer ratio comparison between your selected timeframe and the prior period to understand how the ratio changes over time and your optimizations or market shifts impact it.

  December 28

  • Enhancement
    • Expanded AI platform visibility in Crawl-to-Refer Ratio. The dashboard now displays the top six AI platforms based on AI request volume, matching the top six entries in the AI-Agent Analysis table.