Release History

Telerik UI for ASP.NET AJAX 2025.4.1321

January 21, 2026

Common

NEW

• Telerik Licensing minimal required version is updated to 1.6.36.
• Multiple accessibility and keyboard navigation improvements in multiple controls (RadListBox, OrgChart, TabStrip, Date/Time Pickers, MediaPlayer)
• Telerik Document Processing: Introduced API for automatic file format detection.

Calendar

FIXED

• Date and Time Pickers show picker button on wrong side in RTL with Bootstrap skin and Lightweight rendering

Docking

FIXED

• Dock width increases each time it is dropped with animation enabled

Editor

FIXED

• StripCssExpressions filter causes performance degradation
• Incorrect event args passed to RadEditor OnClientCommandExecuting when RadTreeList is present on the page
• PdfExportFilter filter strips the width attribute from table elements when switching to HTML mode

Grid

FIXED

• tableView.clearSort() does not remove sorted column visual state in client-side bound Grid

ListBox

NEW

• Add WAI-ARIA support for RadListBox

FIXED

• RadListBox lacks visible keyboard focus and proper ARIA support
• Required WAI-ARIA attributes missing in RadListBox button area toolbar and buttons

MediaPlayer

NEW

• Add Loop boolean property for video repeat support

OrgChart

NEW

• Keyboard navigation and Section 508 accessibility support

PdfProcessing

NEW

• Handled documents with invalid byte offsets due to content added at the beginning of the file.
• Document with invalid cross-reference stream is not loaded correctly.
• Introduced support for vertical alignment of table cells.
• Handled the import of incrementally updated documents with invalid cross-reference offsets.
• Handled the import of documents containing integers bigger than int.MaxValue.
• Introduced API used to sign documents using only the end certificate of a certificate chain.
• Introduced a mechanism for changing the Standard font when exporting a PDF/A Compliance document.
• Handled import of documents with a negative cross-reference stream offset.
• Handled the import of documents with invalid offset and no space before dictionary keys.
• Added support for documents with an invalid stream cross-reference table.
• Introduced support for Border annotation property.
• Provided support for specifying the MIME type of embedded files.

FIXED

• An InvalidOperationException: 'The signature was not properly initialized for external signing. The signing delegate is missing.'.
• Resaving a document with Acrobat throws an error due to invalid Info dictionary in document trailer.
• A MissingMethodException is thrown when converting PDF stream to PdfArray.
• Mangled Right-To-Left (RTL) content when multiple lines of text are drawn.
• The font subset is not recalculated when import-export a document and FontEmbeddingType.Subset set.
• Some characters are not properly resolved from the Encoding differences table.
• PdfStreamWriter: InvalidOperationException is thrown when creating multi-page document with umlaut on the last page.
• InvalidOperationException: 'isContentReleased' when exporting.
• The embedded font program is not consistent with the Widths entry of the font dictionary.
• CheckBoxWidget appearance is not correctly displayed when importing document with PdfProcessing.

Splitter

FIXED

• Dragging the Splitbar moves the whole page slightly on mobile devices
• SplitBar does not move smoothly on mobile devices, only shifts a few pixels when dragged

SpreadStreamProcessing

FIXED

• Files exported with SpreadStreamProcessing cannot be read by OleDB consumers.

TabStrip

FIXED

• Focused tab CSS class not removed when clicking tabs with mouse after keyboard navigation

WordsProcessing

FIXED

• The w:multiLine property of a text content control is lost during import.
• PdfFormatProvider: Tab stop distances are not calculated correctly when a hanging indent is applied.
• HtmlFormatProvider: NullReferenceException is thrown when exporting a document that contains styles with no ParagraphMarkerProperties.
• Content is moved to previous page after applying styling to the footer and exporting to PDF format.