2026 Releases

Updated on Feb 11, 2026

This article lists the breaking or important changes in the 2026 releases of Kendo UI. For the complete list of changes in the UI components, see the product release history.

Kendo UI 2026 Q1

TreeView Enhanced Rendering (HTML and CSS)

Starting with the 2026 Q1 release, the TreeView adopts enhanced rendering that updates the generated HTML and the CSS hooks used for styling.

Key HTML Structure Changes

Wrapper class renamed

Before: Position-based wrapper classes were used:

• k-treeview-top
• k-treeview-mid
• k-treeview-bot

After: A single unified wrapper class is used:

• k-treeview-item-content

If you have custom CSS or jQuery selectors, replace selectors that target the positional classes with .k-treeview-item-content.

CSS variable for indentation level

Each .k-treeview-item now renders a --kendo-treeview-level CSS custom property that the theme uses to calculate indentation via padding-inline-start.

Example:

html

<li class="k-treeview-item" style="--kendo-treeview-level: 1;">
    ...
</li>
<li class="k-treeview-item" style="--kendo-treeview-level: 2;">
    ...
</li>

State classes moved

Before: State classes (k-hover, k-focus, k-selected, k-disabled) were applied to the .k-treeview-leaf element.

After: State classes are applied to the .k-treeview-item-content wrapper.

Update any custom selectors accordingly, for example:

css

/* Before */
.k-treeview .k-treeview-leaf.k-selected { /* ... */ }

/* After */
.k-treeview .k-treeview-item-content.k-selected { /* ... */ }

Component Appearance Defaults Removed

Starting with the R1 2026 release, Kendo UI for jQuery components no longer render default appearance CSS classes. Previously, components automatically added size, rounded, fillMode, and themeColor classes to their DOM elements. Instead, these properties default to undefined, allowing the theme's CSS to control the component styling.

What Changed

Previously, components had hardcoded defaults like:

• size: "medium"
• rounded: "medium"
• fillMode: "solid"
• themeColor: "base"

Now, these properties default to undefined. When undefined, no CSS modifier classes (like k-button-md, k-rounded-md, k-button-solid) are added to the component markup. The theme's base CSS selectors control the default appearance.

Components previously rendered with explicit styling classes like:

html

<!-- Before -->
<button class="k-button k-button-md k-rounded-md k-button-solid k-button-solid-base">Click Me</button>

Now render with minimal base classes:

html

<!-- After -->
<button class="k-button">Click Me</button>

The visual appearance remains the same because Kendo Themes v13+ apply default styles to base classes.

Removed CSS Classes by Category

Size Classes (No Longer Rendered by Default)

Class	Component Types
k-button-sm	Buttons
k-button-md	Buttons
k-button-lg	Buttons
k-input-sm	Input components
k-input-md	Input components
k-input-lg	Input components
k-picker-sm	Picker components
k-picker-md	Picker components
k-picker-lg	Picker components
k-checkbox-sm	CheckBox, TreeView
k-checkbox-md	CheckBox, TreeView
k-checkbox-lg	CheckBox
k-chip-sm	Chip, ChipList
k-chip-md	Chip, ChipList
k-chip-lg	Chip
k-badge-sm	Badge
k-badge-md	Badge
k-badge-lg	Badge
k-avatar-sm	Avatar
k-avatar-md	Avatar
k-avatar-lg	Avatar
k-loader-sm	Loader
k-loader-md	Loader
k-loader-lg	Loader
k-calendar-md	Calendar, MultiViewCalendar
k-table-md	Grid, TreeList, PivotGrid, and other table-based components
k-toolbar-md	Toolbar
k-form-md	Form

Rounded Classes (No Longer Rendered by Default)

Class	Description
k-rounded-sm	Small border radius
k-rounded-md	Medium border radius
k-rounded-lg	Large border radius
k-rounded-full	Full/pill border radius

FillMode Classes (No Longer Rendered by Default)

The combined fillMode-themeColor class pattern has been split into separate classes:

Versions prior to 2026.1	Versions 2026.1 and later
k-button-solid-base	k-button-solid
k-button-solid-primary	k-button-solid k-button-primary
k-button-solid-secondary	k-button-solid k-button-secondary
k-button-flat-base	k-button-flat
k-button-flat-primary	k-button-flat k-button-primary
k-chip-solid-base	k-chip-solid
k-chip-solid-primary	k-chip-solid k-button-primary

Default fillMode classes (k-button-solid, k-input-solid, etc.) are no longer rendered when using theme defaults:

Class	Component Types
k-button-solid	Buttons (removed when default)
k-button-flat	Flat buttons (rendered only when explicitly set)
k-button-outline	Outline buttons (rendered only when explicitly set)
k-input-solid	Input components (removed when default)
k-input-flat	Input components (rendered only when explicitly set)
k-input-outline	Input components (rendered only when explicitly set)
k-picker-solid	Picker components (removed when default)
k-picker-flat	Picker components (rendered only when explicitly set)
k-picker-outline	Picker components (rendered only when explicitly set)
k-chip-solid	Chip (removed when default)
k-chip-outline	Chip (rendered only when explicitly set)
k-badge-solid	Badge (removed when default)
k-badge-outline	Badge (rendered only when explicitly set)
k-avatar-solid	Avatar (removed when default)
k-avatar-outline	Avatar (rendered only when explicitly set)

Affected Components

The following components no longer render default appearance classes:

Input Components

Component	fillMode	size	rounded	themeColor
AutoComplete	Removed	Removed	Removed	-
ComboBox	Removed	Removed	Removed	-
DateInput	Removed	Removed	Removed	-
DatePicker	Removed	Removed	Removed	-
DateRangePicker	Removed	Removed	Removed	-
DateTimePicker	Removed	Removed	Removed	-
DropDownGrid	Removed	Removed	Removed	-
DropDownList	Removed	Removed	Removed	-
DropDownTree	Removed	Removed	Removed	-
MaskedTextBox	Removed	Removed	Removed	-
MultiSelect	Removed	Removed	Removed	-
MultiSelectTree	Removed	Removed	Removed	-
NumericTextBox	Removed	Removed	Removed	-
OTPInput	Removed	Removed	Removed	-
TextArea	Removed	Removed	Removed	-
TextBox	Removed	Removed	Removed	-
TimeDurationPicker	Removed	Removed	Removed	-
TimePicker	Removed	Removed	Removed	-
ColorPicker	Removed	Removed	Removed	-
ColorGradient	-	Removed	-	-
ColorPalette	-	Removed	-	-
Signature	Removed	Removed	Removed	-

Button Components

Component	fillMode	size	rounded	themeColor
Button	Removed	Removed	Removed	Removed
ButtonGroup	Removed	-	-	-
SplitButton	Removed	Removed	Removed	Removed
DropDownButton	Removed	Removed	Removed	Removed
MenuButton	Removed	Removed	Removed	Removed
FloatingActionButton	Removed	Removed	Removed	Removed

Chip Components

Component	fillMode	size	rounded	themeColor
Chip	Removed	Removed	Removed	Removed
ChipList	-	Removed	-	-

Indicator Components

Component	fillMode	size	rounded	themeColor
Avatar	Removed	Removed	Removed	Removed
Badge	Removed	Removed	Removed	Removed
Loader	-	Removed	-	Removed

Starting with the 2026 Q1 release, the Badge component renders with the primary appearance by default. Because appearance defaults are now theme-controlled, the themeColor option will be undefined when not set, but the theme applies the primary styling. To preserve the previous (secondary) look, explicitly set themeColor: 'secondary'.

Navigation Components

Component	fillMode	size	rounded	themeColor
BottomNavigation	Removed	-	-	Removed
Breadcrumb	-	Removed	-	-
TabStrip	-	Removed	-	-

Selection Components

Component	fillMode	size	rounded	themeColor
CheckBox	-	Removed	Removed	-
RadioButton	-	Removed	-	-
Switch	-	Removed	Removed	-

Data Components

Component	fillMode	size	rounded	themeColor
Grid	-	Removed	-	-
ListBox	-	Removed	-	-
Pager	-	Removed	-	-
TreeView	-	Removed	-	-

Layout & Containers

Component	fillMode	size	rounded	themeColor
AppBar	-	-	-	Removed
Dialog	-	-	-	Removed
Window	-	-	-	Removed
ToolBar	Removed	Removed	-	-
Form	-	Removed	-	-

Notification

Starting with 2026 Q1 version when no type parameter is passed the the show method, the Notification will be displayed with default colors. Previously, the default value of the type property was info. If you need to acheive the previous behavior you can use the approaches demonstrated below:

js

var notification = $("#notification").kendoNotification().data("kendoNotification");

notification.show("Some text", "info");

//or

notification.info("Some text");

Icons

Component	fillMode	size	rounded	themeColor
Icon	-	Removed	-	Removed
SVGIcon	-	Removed	-	Removed

Components with Internal Template Changes

The following components have internal buttons, inputs, checkboxes, or other elements that previously had hardcoded default appearance classes. These classes have been removed:

• Calendar, MultiViewCalendar
• ColumnMenu
• Dialog
• Editor
• FileBrowser
• FileManager
• Filter, FilterMenu
• Gantt
• Grid, TreeList, PivotGrid
• Map
• MediaPlayer
• Menu
• Pager
• PanelBar
• PDFViewer
• Scheduler
• Spreadsheet
• TabStrip
• TaskBoard
• Timeline
• TreeView
• Upload

Migration Guide

If You Need Explicit Styling

If your application relies on the previous default classes, you can explicitly set the options:

javascript

// Before (implicit defaults)
$("#button").kendoButton();
// Rendered: <button class="k-button k-button-md k-rounded-md k-button-solid k-button-solid-base">

// After (explicit sizing)
$("#button").kendoButton({
    size: "medium",
    rounded: "medium",
    fillMode: "solid",
    themeColor: "base"
});
// Rendered: <button class="k-button k-button-md k-rounded-md k-button-solid k-button-solid-base">

If You Have Custom CSS Targeting Size Classes

Update your CSS selectors to target base classes or use explicit options:

css

/* Before - targeting medium buttons */
.k-button.k-button-md {
    /* custom styles */
}

/* After - target base class (theme provides defaults) */
.k-button {
    /* custom styles */
}

/* Or set explicit size and target that */
.k-button.k-button-md {
    /* only applies when size: "medium" is explicitly set */
}

If You Use the "none" Value

The "none" value has been removed from size, fillMode, and rounded options. If you were using "none" to disable styling:

javascript

// Before
$("#button").kendoButton({ size: "none" }); // No longer supported

// After - omit the option entirely
$("#button").kendoButton();

Learn how to restore previous default appearance values for Kendo UI for jQuery components in the article linked here.

Theme Version Update

The Kendo themes have been updated to version 13.0.0 (from 12.x). The new theme version provides default styling via CSS instead of requiring JavaScript to add explicit modifier classes.

Benefits

1. Cleaner DOM - Components render fewer CSS classes
2. Flexible Theming - Easier to customize default appearance via CSS
3. Smaller Markup - Reduced HTML output size
4. Centralized Defaults - Styling defaults managed in CSS, not JavaScript