--- title: Upgrade to CMS Core 12.17.0 slug: cms-12/docs/upgrade-to-cms-core-12170 docTags: createdAt: 2026-08-10T15:55:58.000Z --- Optimizely Content Management System (CMS) Core (`EPiServer.CMS.Core`) version 12.17.0 introduces a reliance on SixLabors ImageSharp for image manipulation. :::hint{type="danger"} **Warning** Potential breaking change: SixLabors ImageSharp v3 fixes WEBP issues in SixLabors ImageSharp v2, but there are binary-incompatible changes between v2 and v3. For partners, who use ImageSharp v2 directly in their code base, upgrading to CMS 12.17.0 could be a breaking change. ::: The image service's implementation was moved to a separate package, `EPiServer.ImageLibrary.ImageSharp`, and released independently from CMS Core. There are two major versions of the package: - v1 of the package depends on ImageSharp v2. Reference 1.0.6 or later for the security patch. - v2 of the package depends on ImageSharp v3. Reference 2.0.8 or later for the security fixes in `SixLabors.ImageSharp` 3.2.0. :::hint{type="warning"} **Important** You should use v2 unless ImageSharp API is consumed directly in your code. ::: ## Projects with EPiServer.CMS umbrella package reference `EPiServer.CMS` has a reference to `EPiServer.CMS.Core` 12.17.0. Update the umbrella package, and then you are done. The WEBP issues are fixed by updating `EPiServer.ImageLibrary.ImageSharp`. ```json ``` If you are on `EPiServer.CMS 12.22.x` and below and still want to fix WEBP issues, include these package references: ```json ``` ## Projects with direct reference to CMS Core Besides upgrading CMS Core to v12.17.0 and above, you also need an additional reference. Use V1 only when your code consumes the `SixLabors.ImageSharp` API directly. :::hint{type="warning"} **Important** Reference `EPiServer.ImageLibrary.ImageSharp` 1.0.6 or later to include the security patch for advisory [GHSA-rxmq-m78w-7wmc](https://github.com/advisories/GHSA-rxmq-m78w-7wmc). ::: ```json ``` Missing this package would cause an exception to be thrown on startup that says, "*It needs to either update*`EPiServer.CMS` *package to the latest version, which has dependency on* `EPiServer.ImageLibrary.ImageSharp` *package, or install* `EPiServer.ImageLibrary.ImageSharp` *package directly into your project.*"