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2025 Releases

This article lists the breaking or important changes in the 2025 releases of Telerik UI for ASP.NET Core.

Telerik UI for ASP.NET Core Q3 2025 (2025.3.825)

Chat

The Chat component has been completely redesigned.

Toolbar() and User() configurations have been deprecated.
The following client-side methods have been deprecated: getUser(), renderAttachments(), renderMessage(), renderSuggestedActions(), renderUserTypingIndicator(), clearUserTypingIndicator(), removeTypingIndicator(), and toggleToolbar(). For more information on the new client-side methods, refer to the client-side API.

HtmlHelper Chat Options

Old	New
`User(user => user.Name())`	`AuthorId()` `AuthorIdField()` `AuthorNameField()`
`User(user => user.IconUrl())`	`AuthorImageUrlField()` `AuthorImageAltTextField()`

HtmlHelper Chat Events

Old	New
`ActionClick`	`SuggestionClick` and `FileMenuAction`
`Post`	`SendMessage`
`TypingStart` and `TypingEnd`	`Input`
`ToolClick`	No longer available.

TagHelper Chat Options

Old	New
`<user name="authorName" />`	`author-id="1"` `author-id-field="AuthorId"` `author-name-field="AuthorName"`
`<user icon-url="url" />`	`author-image-url-field="AuthorImageUrl"` `author-image-alt-text-field="AuthorImageAltTextField"`

TagHelper Chat Events

Old	New
`on-action-click`	`on-suggestion-click` and `on-file-menu-action`
`on-post`	`on-send-message`
`on-typing-start` and `on-typing-end`	`on-input`
`on-tool-click`	No longer available.

Telerik UI for ASP.NET Core Q3 2025 (2025.3.812)

The ActionSheet's action buttons now accept enums for the FillMode, Rounded, ThemeColor, Size properties instead of strings. The ActionSheetItem.Group property now accepts the ActionSheetItemGroup enum instead of a string.

AIPrompt

The ShowOutputRating() option of the AIPrompt HtmlHelper and show-output-rating attribute of AIPrompt TagHelper is deprecated. Use OutputActions() configuration option that is more flexible.
The OutputRatingChange event is deprecated. Use OutputAction instead.
The OutputCopy event is deprecated. Use OutputAction event instead.
The k-prompt-suggestion class on the role='listitem' element has been replaced with the k-suggestion class.

TabStrip

In versions before 2025 Q3, the icon-class configuration option sets a sprite CSS class in the items of the TabStrip TagHelper. Starting with version 2025 Q3, the icon-class attribute applies a custom CSS class to the default SVG tab icon element. The sprite-css-classes attribute sets sprite icons to the TabStrip tabs.

Before Q3 2025:

Razor

<tabstrip-item icon-class="netherlandsFlag" text="Netherlands"></tabstrip-item>

After Q3 2025:

Razor

<tabstrip-item sprite-css-classes='new string[] {"netherlandsFlag"}' text="Netherlands"></tabstrip-item>

UIPrimitives

The Telerik UI for ASP.NET Core 2025 Q3 release introduces changes in the naming of several properties in the UIPrimitives.cs class:

Old	New
`UIPrimitives.Grid.Toolbar`	`UIPrimitives.Grid.GridToolbar`
`UIPrimitives.Slider.Item`	`UIPrimitives.Slider.SliderItem`
`UIPrimitives.Window.Content`	`UIPrimitives.Window.WindowContent`
`UIPrimitives.PanelBar.Item`	`UIPrimitives.PanelBar.PanelBarItem`
`UIPrimitives.PanelBar.Content`	`UIPrimitives.PanelBar.PanelBarContent`
`UIPrimitives.PanelBar.Header`	`UIPrimitives.PanelBar.PanelBarHeader`
`UIPrimitives.PanelBar.Group`	`UIPrimitives.PanelBar.PanelBarGroup`

Telerik UI for ASP.NET Core Q2 2025

Unified Distribution for Trial and Commercial Packages

With the goal of streamlining user experience, the trial and commercial packages have been consolidated into a single unified distribution for Telerik UI for ASP.NET Core. Access is now managed through a license key file, eliminating the need for separate trial download. For more information, please refer to Setting Up Your License Key.

Target Framework

With the Q2 2025 release, Telerik UI for ASP.NET Core support for .NET 6 has been dropped as .NET 6 has reached the end of its lifecycle on November 12, 2024. You can update to a supported LTS and STS versions of .NET Core.

The IconClass() option of the PopOver HtmlHelper and the icon-class attribute of the PopOver TagHelper now expect a string instead of a JavaScript handler or a template delegate (System.Func<Object,Object>).

Razor
    <span id="target">Hover</span>

    @(Html.Kendo().Popover()
        .For("#target")
        .Body("Content description")
        .Actions(a =>
        {
            // "IconClass" adds a CSS class to the icon element inside the action button.
            a.Add().Text("refresh").Icon("arrow-rotate-cw").IconClass("refresh-icon");
        })
    )
Razor
    @addTagHelper *, Kendo.Mvc

    <span id="target">Hover</span>

    <kendo-popover for="#target" body="Content description">
        <actions>
            <!-- "icon-class" adds a CSS class to the icon element inside the action button.-->
            <action text="refresh" icon="arrow-rotate-cw" icon-class="refresh-icon"></action>
        </actions>
    </kendo-popover>

HtmlHelper Grid

Old	New
`Position(GridPagerPosition.Top)`	`Position(PagerPosition.Top)`

TagHelper Grid

Old	New
`position="GridPagerPosition.Top"`	`position="PagerPosition.Top"`

The Grid component now provides a new property to disable or hide the inactive tools when editing. Its ToolBar buttons like Save Changes and Cancel will be hidden by default. When the ToolBar.ShowInactiveTools option is enabled the inactive tools will be displayed as disabled.

More details you can find in the dedicated Grid ToolBar article.

Telerik.Zip

As of the Q2 2025 release, the following NuGet packages and assemblies no longer have a dependency to the Telerik.Zip library:

Telerik.Core.Export
Telerik.Web.Pdf
Telerik.Web.Spreadsheet

The Telerik.Zip library will continue to be shipped as a standalone library.

The responsive behavior of the Pager has been enhanced, which introduces the following changes:

The Pager's sizing is no longer based on breakpoints. Instead, the optimized responsive behavior renders as many elements as possible within the available space.
Input Type—When the Input() option of the Pager is enabled, the TextBox next to the navigation arrows is replaced with a NumericTextBox, and the numeric page number buttons are no longer rendered.
Page Selection—The page selection drop-down has been replaced with a NumericTextBox for improved user interaction.
NumbersSelectLabel() Property—The NumbersSelectLabel() option in the Messages() configuration has been removed as it is no longer needed with the replacement of the page selection drop-down.

These changes to the Pager affect all components that use a built-in pager, including the Grid, PDFViewer, and other data management components.

Rendering Changes

The Telerik UI for ASP.NET Core 2025 Q2 release introduces changes in the rendering of the following components:

AIPrompt

The k-white-space-pre-line class has been removed from the k-card-body element where the output from the prompt is rendered.

DockManager

The k-header class has been removed from the TabStrip element.

ExpansionPanel

The k-d-none class on the k-expander-content-wrapper element has been replaced with the k-hidden class.

Gantt

The k-alt class has been removed from the rows in the TreeList and the timeline in the Gantt.

Grid

The k-alt class has been removed from the tr.k-table-alt-row elements.
The k-grid-draggable-header class and the draggable=true attribute have been added to the k-grid-header element when grouping or column reodering is enabled.
The k-touch-action-none class has been removed from the draggable cell elements due to the addition of the k-grid-draggable-header.
The k-drag-cell class (when row-reordering is enabled) has been removed from the k-table-th element.

Menu

The k-menu-separator class has been replaced with the k-separator-horizontal class.

Spreadsheet

The k-tabstrip-item class has been added to the k-item elements in the sheet bar.

TreeList

The k-treelist-group class has been removed from the parent nodes.
The k-drag-cell class (in row-reordering scenario) has been removed.

Telerik UI for ASP.NET Core Q1 2025

License Activation

Starting with 2025 Q1, all users of Telerik UI for ASP.NET Core will need to apply a valid license key file to both new and existing projects. For details, see our Licensing Documentation.