---
title: Optimizely Forms for CMS 13
slug: cms-13/docs/episerver-forms-addon
docTags: 
createdAt: 2026-07-30T20:22:08.256Z
---

Optimizely Forms 6.0.0 targets Optimizely Content Management System (CMS) 13 and .NET 10. Upgrade to this version to run Forms on the CMS 13 platform. This release modernizes configuration and dependency injection (DI) and removes APIs deprecated in earlier versions.

:::hint{type="warning"}
**Important**
Optimizely Forms 6.0.0 does not work with Experience. Migrate to CMS 13 before upgrading to Forms 6.0.0.
:::

## What changed

Identify which areas of your project require updates by reviewing the following changes:

- **Explicit DI registration** – Forms no longer auto-registers services. Call `services.AddForms()` in `Program.cs`.
- **Configuration moved to** `appsettings.json` – The `Forms.config` XML file no longer exists. Configure all settings under the `Forms` key in `appsettings.json`.
- **Removed deprecated APIs** – Interfaces, methods, and classes marked `[Obsolete]` in earlier versions no longer exist. Removals include `IEPiServerFormsCoreConfig`, `IExcludeValidatorTypes`, `ActiveExternalFieldMappingTable`, and several `FormBusinessService` overloads.
- `System.Text.Json` **replaces** `Newtonsoft.Json` – `PropertyGenericList<T>` uses `System.Text.Json` with camelCase naming. Update custom model types that rely on `Newtonsoft.Json` attributes.
- **CMS 13 API alignment** – Scheduled jobs, property definition types, and other platform APIs use their CMS 13 equivalents.

See [Breaking changes in Optimizely Forms 6.0.0](docId\:LdMgdviP4KqcB6DFNCu2C) and [Migrate to Optimizely Forms 6.0.0](docId\:VVgrkBtQbh7pMqjx3f1_n).