---
title: Breaking changes in CMS 11
slug: cms-11/dev-docs/breaking-changes-cms-11
docTags: 
createdAt: 2026-07-22T19:45:20.632Z
---

To view the complete list of changes, see the release notes feed.

Some changes are binary breaking but do not necessarily require code changes but rather a project recompilation. Breaking changes are changes in method signatures or behavior of methods compared to the documented API in the previous version, described in this document.

## New NuGet packages

In Optimizely Content Management System (CMS 11), some functionality, such as **TinyMCE**, was moved to separate NuGet packages. These packages have their version number and may or may not be upgraded with the core CMS packages.

**XForms** has also been moved to its own NuGet package. This means that the **Forms viewer gadget**, which was deprecated in CMS 10, is now also removed.

Most upgrades do not require code changes but require a re-compilation. You should have the correct packages installed. A missing package causes compilation errors after upgrading a site. See [New NuGet packages](/epiui/CMS/Content/documentation/upgrading/optimizely-cms/cms-11/new-nuget-packages,,183973/?epieditmode=False) for which packages you must manually add.

## Separate NuGet packages for ASP.NET dependencies ([CMS-8106](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8106))

- The integration with ASP.NET has moved to separate packages `EPiServer.Framework.AspNet` and `EPiServer.Cms.AspNet`.
- `EPiServer.MirroringService.MirroringMonitoring.MirroringMonitoringModule` has moved from `EPiServer.Enterprise` to `EPiServer.Cms.AspNet`. It must be manually changed in `web.config` for the mirroring module.
- Usage of StructureMap as IOC container was moved to a separate package, `EPiServer.ServiceLocation.StructureMap.`
- .NET Framework 4.61 is required.
- MVC 5.2.3 is required.
- `CreatePropertyControl` was removed from `PropertyData`. Use `IPropertyControlFactory` instead to register and create controls for `PropertyData` types.
- Providers (for example `ContentProvider`, `BlobProvider`) no longer inherit `ProviderBase`. If a provider that supports configuration through `web.config` has an initialization method with the signature void `Initialize(string name, NameValueCollection config)`, it will be called during the initialization phase
- `IServiceLocator` no longer supports named instances. The specific implementation in `EPiServer.ServiceLocation.StructureMap` supports named instances.
- Some methods in `IServiceLocator` were removed from the interface and are now extension methods in `EPiServer.ServiceLocation` namespace.
- `EPiServer.Search.SearchSettings.Config` was replaced by `EPiServer.Search.SearchSettings.Options`.
- It is no longer supported to get an `ILogger` instance from IOC container.
- Calls to logger that occur before `IConfigurableModules` are created, are not guaranteed to be persisted.
- The setting for logger factories `episerver:LoggerFactoryType` must now always be qualified with assembly name, even for built-in logger factories.
- The method `IStringFragment.GetControl` was removed. Use `IStringFragmentControlResolver` instead to create controls for string fragments.
- Configuration sections `EPiServerFrameworkSection`, `StaticFileSection`, `EPiServerDataStoreSection` and `SearchSection` were moved to assembly `EPiServer.Framework.AspNet`.
- Property `Database` on `DataAccessBase` was removed and is replaced by the property `Executor`.
- `PageData.LinkUrl` no longer contains the query parameter `epslanguage`.
- `ContentProviders` can no longer use `CacheSettings.Filenames` (previously obsoleted) to set up dependencies to files.
- `EPiServer.Web.InitializationModule` was moved to `EPiServer.Cms.AspNet` assembly and can be used as a dependency module for other modules that want to run after Optimizely CMS is initialized when running as an ASP.NET application. There is a new module `EPiServer.Initialization.CmsCoreInitialization` in assembly `EPiServer`. It can be a dependency module for modules that want to run after CMS Runtime is initialized when running CMS outside ASP.NET context.
- Previously obsoleted methods Rebase/MakeRelative on type `EPiServer.Web.UrlBuilder` in assembly `EPiServer` were moved to extensions method defined in assembly `EPiServer.Cms.AspNet`. Type `UrlBuilder.RebaseKind` is also moved to `EPiServer.Web.RebaseKind` in `EPiServer.Cms.AspNet` assembly.
- `AccessControlList.Save` was deprecated and is no longer supported. Use `IContentSecurityRepository` instead.

## Manually and automatically registered templates share the same behavior ([CMS-4161](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-4161))

- Templates registered manually using `ITemplateRepository.AddTemplates` are now associated with the model type for which they are added, rather than the model type indicated through any `IRenderTemplate` interface of the template. This may affect the template selection during runtime, as the model type association is used to decide which template to use when rendering a content item. This change does not affect automatically registered templates, as they are already registered using the type specified by the IRenderTemplate interface.
- The default implementation of `ITemplateRepository.AddTemplates` now checks if a template exists before adding it. If the template is already registered, it does not add another one.
- The default implementation of `ITemplateRepository.AddTemplates` now makes sure that all template models are read-only before adding them to the repository.

## `PropertList<T>` ([CMS-7212](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-7212))

- `EPiServer.Core.Transfer.IRawContentRetriever` no longer populates the value of each `RawProperty`. Instead, this is done by calling the `IPropertyExporter.ExportProperties` method.
- `EPiServer.Core.Transfer.IPropertyImporter` has changed slightly to match the new `IPropertyExporter` interface.
- `PropertyData.ToRawString()` is no longer called when exporting data. If a Custom `PropertyData` type had previously overridden the `ToRawValue` method, it must now move that functionality to a class that implements `IPropertyExportTransform` and register it with the Container.
- PropertyJson-based properties, such as `PropertyList<T>`, no longer rely on `IObjectSerializer` and container-registered `JsonConverters` for their serialization. They now use `Newtonsoft.Json.JsonConvert` directly. This means that `JsonConverters` must be defined as attributes on the classes and properties to which they apply.

## Explicit IVersionable implementation on PageData is removed ([CMS-7700](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-7700))

- `PageData` no longer exposes a separate explicit implementation of `IVersionable.StartPublish` and `IVersionable.StopPublish`.

## Performance improved when loading large amounts of uncached content ([CMS-7735](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-7735))

- `CreateWritableClone` is used to create content instances when loading from the database.

## Target .NET Standard 2 in CMS.Core and Framework ([CMS-8133](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8133))

- `ThumbnailManager` was moved to `EPiServer.Cms.AspNet`.
- `Castle.Core` dependency was changed to `[4.2.1, 5.0)`.
- `Castle.Windsor` dependency was changed from `[4.1.0, 5.0)`.

## Scheduled jobs have a shorter default content cache expiration ([CMS-8653](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8653))

- Content loaded from a database and added to cache by scheduled jobs has a shorter cache expiration (default 1 minute).

## Memory usage optimization: Data class PropertyData does not expose services ([CMS-8659](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8659))

- SettingsID is obsoleted. Use extension method `GetSettingsID` or service `IPropertyDataSettingsHelper` instead.
- `SettingsContainer` is obsoleted. Use the extension method `GetSettingsContainer` or service `IPropertyDataSettingsHelper` instead.
- `TranslateDisplayName()` or `TranslateDescription()` was moved to `extension` method.

## Other changes

### CMS Core

- [CMS-7749](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-7749) The Provider property is no longer supported, as it is impossible to expose a fully thread-safe IList implementation.
- [CMS-7791](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-7791) Simple address is now the last registered router.
- [CMS-6988](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-6988) MoveContentEventArgs.ContentLink is updated when content is moved between providers.
- [CMS-9129](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-9129) Unsupported HostType's Service, Installer, and VisualStudio were obsoleted.

### CMS UI

- [CMS-1130](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-1130) The `UIHint.BlockFolder` and `UIHint.MediaFolder` were obsoleted and are replaced by UIHint.AssetsFolder.
- [CMS-1252](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-1252) Error message now displayed when updating partially rendered content.
- [CMS-6217](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-6217) Content repository descriptor keys are now not case-sensitive.
- [CMS-6815](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-6815) `IContentChangeManager.Move(IContent source, IContent destination, bool createAsLocalAsset)` now returns the `ContentReference` of the moved content instead of void. This adds support for the scenario where content is assigned a new `ContentLink` value when it is moved between different content providers.
- [CMS-8229](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8229) `ApplicationUIUserManager<TUser>.ResetPassword(IUIUser user)` now throws a not supported exception. This is because ASP.NET Identity does not support generating new passwords for security reasons. Use the new method `ResetPassword(IUIUser user, string newPassword)` instead.
- [CMS-8802](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8802) The deprecated `datetime.js` methods `serialize()` and `deserialize()` were removed.
- [CMS-8816](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8816) The deprecated slash method was removed from `epi/string`.
- [CMS-8817](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8817) `epi-cms/widget/HierarchicalList` was replaced by `epi-cms/asset/HierarchicalList`.
- [CMS-8830](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8830) The deprecated property `SiteDefinitionResolver` on `ContentSearchProviderBase` was removed. Use `SiteResolver` instead.
- [CMS-8832](/epiui/CMS/Content/documentation/Release-Notes,,82523/ReleaseNote/?epieditmode=False\&epsremainingpath=ReleaseNote/\&releaseNoteId=CMS-8832) The deprecated `EPiServer.Shell.Web.Mvc.Html.DojoExtensions` was removed, use `.ConfigureDojo` instead.
- `DateTime` properties on the visitor group criterion model are serialized to ISO 8601 when being sent to the client.
- The `MissingConfigurationException` now inherits directly from `Exception`.
- The `UIHint.LongString` was obsoleted and should be replaced with `UIHint.Textarea`.
- Properties that use `LegacyPropertyEditorDescriptor` should be explicitly annotated with `UIHint.Legacy`.
- Obsoleted constructors are removed where there are public constructors available that can be used instead.
- Obsoleted properties were removed from `PropertyUpdateResult`, `ComponentContainer`, `ContentSearchProviderBase`, and `CmsModuleViewModel`.
- Obsoleted classes `ZipFileVirtualPathProvider` and `SecurityEntityUtility` were removed.
- Obsoleted methods were removed from `UIDescriptorRegistry`.
- `_GrigWidgetBase` now emits `selectionChanged` when deselecting row. Previously, it was triggered only when a row was selected.
- The obsoleted delegate `DependencyGetter` was removed.
- The obsoleted methods `watchModelChange` and `unwatchModelChange` in `epi/shell/_Command` was changed from public to internal.
- The class `ContentReferenceStore` that was available by `epi.cms.contentreferences` key is now obsoleted.

## Manual changes required to legacy feature Mirroring

An updated DLL is available in the `EPiServer.CMS.Core` NuGet package (`packages/EPiServer.CMS.AspNet.11.1.0/tools/MirroringService/`), which you must manually patch when upgrading.

- Change `EPiServer.MirroringService.MirroringTransferProtocol.WCF.MirroringTransferClient,EPiServer.Enterprise` to `EPiServer.MirroringService.MirroringTransferProtocol.WCF.MirroringTransferClient,EPiServer.Cms.AspNet`
- Change the type `EPiServer.Security.WindowsMembershipProvider,EPiServer` to `EPiServer.Security.WindowsMembershipProvider, EPiServer.Cms.AspNet` in `web.config`.