---
title: Forms 4.5 - Important changes
slug: cms-12/docs/forms-4-5-important-changes
docTags: 
createdAt: 2026-08-10T15:55:55.000Z
---

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

## EPiServer.Forms

This release uses data attributes for binding functionality instead of CSS classes

- From version 4.5, view-templates of build-in elements use `data-` attribute instead of CSS class. It gives the designer more freedom to change CSS classes in the view-templates without worrying about breaking Forms functionality. See also [CSS styling and JavaScript](docId\:M6zmQUTL7zxaURkapgpdi) for information on changing CSS classes.
- Built-in elements have attribute `data-f-type`, with the following possible values:
  - form
  - step
  - textbox
  - hidden
  - submitbutton
  - resetbutton
  - range
  - fileupload
  - captcha
  - selection
  - choose
  - navigationbar
- Custom elements must have `data-f-type="custom"` attribute.
- `data-f-modifier` to separate variations of the same type of element. For example, the textbox element has `data-f-type="textbox"` and four variations of modifier:
  - number
  - url
  - number
  - textarea
- Built-in `DataElement` keep data in `<input>`, marked with `data-f-datainput` (Boolean) attribute (instead of using `.FormTextbox__Input` CSS class).
- Element has `data-f-element-nondata` attribute (Boolean) will not be collected on submitting (instead of using `.Form__Element--NonData` CSS class).
- Using `data-f-validationerror` instead of `.Form__Element__ValidationError` to find error message element
- Using `data-f-form-statusmessage` instead of `.Form__Status__Message` CSS class
- Using `data-f-excludedatarebind` instead of `.FormExcludeDataRebind` CSS class
- Captcha element
  - Using `data-epiforms-type="captcha"`
  - Using `data-epiforms-captcha-refresh`, `data-epiforms-captcha-image` instead of  `.FormCaptcha__Refresh`, `.FormCaptcha__Image` CSS classes
- Form NavigationBar
  - `data-epiforms-type="navigationbar"`
  - `data-epiforms-navigation-currentStep`, instead of `.Form__NavigationBar__ProgressBar__CurrentStep`
  - `data-epiforms-navigation-stepcount`, instead of  `.Form__NavigationBar__ProgressBar__StepsCount`
  - `data-epiforms-navigation-progress`, instead of  `.Form__NavigationBar__ProgressBar—Progress`
- Use `data-f-linked-name` instead of `data-epiforms-linked-name` to link DOM element of the same `FormElement`.

:::hint{type="info"}
**Note**
View Template using CSS classes (the old method) still works when using Forms 4.x, but there is no guarantee it will work in future major releases.
:::