---
title: Forms 2 - Breaking changes
slug: cms-12/docs/forms-2-breaking-changes
docTags: 
createdAt: 2026-08-10T15:55:59.000Z
---

:::hint{type="info"}
**Note**
[Optimizely Forms](docId:3SbSlJZIS_3iFmghfQA3J) is supported by MVC-based websites only.
:::

Some changes are binary breaking but do not necessarily require code changes but rather just a project recompilation.

- AFORM-455 `Forms.DLL` is now signed.
- AFORM-540 Actor can now run sync or async with the submission process. With sync-Actor, a developer can modify the response return to the Visitor. See also [Implement a customized Actor](https://world.optimizely.com/documentation/developer-guides/forms/implementing-a-customized-actor/).
- AFORM-551 Autofill API
  - Introduce `IAutofillProvider` and `AutofillService`.
  - Change `IFormElement.GetDefaultValue().`
- AFORM-472] The intention of `RichTextWithPlaceholder` is *Recall field value in previous-step*. With this feature, `RichTextWithPlaceholder` element works like a normal XHTML block (even when no placeholder exists).
- AFORM-418 **Progressive Profiling** for Forms BETA.
- AFORM-480 Built-in **Submit** button now has a Progressive Profiling feature.
- AFORM-526 Option to not load the default style sheet  (`EPiServerForms.css`).

# API changes

## Changed

- `IFormElement` interface has a method: `IFormElement.GetDefaultValue()`.
- AFORM-533 `IPostSubmissionActor` interface has properties to provide information about Field mapping to external systems.
  - Actor can be sync or async
  - Only sync-actor can have/modify the `ResponseBase` object
  - If a third-party developer uses `PostSubmissionActorBase`, their class is not affected.
- AFORM-534 Feed API should be for internal use only.
- AFORM-541 Renamed `IElementTittle` to `IElementTitle`, (fixing a typographical error in naming).
- AFORM-488 Refactored static functions of validation, moved to `ValidationService`.

## Marked as obsolete

- Method of `FormsExtensions` should be treated as Internal use only. They are helper functions and are not critical to providing services to third-party developers.
- Properties
  - `FieldMapping.Name`
  - `FormElement.Code`
  - `FormElement.AttributesString`
  - `IFormElement.Code`
  - `IFormElement.AttributesString`
- Methods
  - `ElementBlockBase.FindParentForm`
  - `FormsExtensions.GetSelectedDatasource`
  - `FormsExtensions.GetMatchedValidator`
- Types
  - `EPiServer.Forms.Core.FieldMapping`
  - `EPiServer.Forms.Implementation.DataSubmissionEngine`
  - `EPiServer.Forms.Implementation.FileSaveItem`
  - `EPiServer.Forms.Implementation.ProgressiveSubmitInfoService`
  - `EPiServer.Forms.Implementation.ProgressiveSubmitInfoService`