Updated Telerik Licensing minimal required version to 1.8.2.
Updated Telerik Document Processing Library (DPL) version to 2026.1.402.
AsyncUpload (Breaking Changes):
CSRF validation is now enabled by default for all upload requests. Applications that do not use ASP.NET Session State must add to appSettings. Applications using WebResourceSession handler are not affected.
The legacy and already obsolete IFrame, Silverlight and Flash upload modules have been removed. RadAsyncUpload now exclusively uses the File API module.
The DisablePlugins property has been removed. Remove any references to it from your markup or code-behind.
The get_loadedModuleName() client-side method has been removed. Remove any calls to it from your client-side code.
The FileFilters property is no longer functional as it relied on the removed Flash and Silverlight modules. Use the HTML5 accept attribute on the file input instead.
The Telerik.Web.UI.RadAsyncUpload.Modules.Flash and Telerik.Web.UI.RadAsyncUpload.Modules.Silverlight client-side objects no longer exist. Remove any JavaScript workarounds referencing them.
ClientDataSource:
Added OData v4 transport option.
Editor:
MediaManager now outputs HTML5 video and audio elements for browser-supported formats (mp4, webm, ogv, mp3, wav, ogg, oga) instead of the obsolete object/embed tags. Legacy formats (e.g. avi, wmv) still use embed. The WMP Properties tab has been replaced with HTML5 attributes (controls, autoplay, loop, muted, preload) for supported formats.
Improved keyboard navigation and screen reader support in RadEditor toolbar dropdowns (FontName, FontSize, RealFontSize, ForeColor, BackColor, InsertSymbol, InsertTable etc.).
NumericTextBox:
Added EnableMobilePattern property for triggering the numeric keyboard on mobile devices.
PdfProcessing:
Optimized the export of Functions.
Improved font handling during document import.
Introduced API for Cloning RadFixedPages and for splitting RadFixedDocument into pages.
Implement AutoTag Tables from document Primitives.
Introduced support for PDF Portfolios.
Implemented Exponential Interpolation Function.
SpreadProcessing:
XlsFormatProvider: Added support for hidden rows.
Added support for Superscript/Subscript formatting option.
Introduced support for notes in XLS format.
Added support for Strikethrough formatting option.
Introduced support for images when importing and exporting XLS documents.
Design rendering failure with Uncaught TypeError: Cannot read properties of null (reading 'commonAncestorContainer') when using ToolbarMode="RibbonBarShowOnFocus".
Fixed issue where keyboard selection is not working in toolbar dropdowns (FontName, FontSize, RealFontSize).
Missing ARIA attributes on the HTML mode textarea when EnableAriaSupport is enabled.
Cell Properties - Preview only shows top-left cell styling when applying changes to multiple top-row cells.
Grid:
Fixed HeaderContext filter menu throwing '_linkElement' undefined error after expand animation ends.
PdfProcessing:
The import performance is reduced when having XObject instances with many Shading elements.
PdfStreamWriter: Merging PDF documents causes blank pages.
Fixed issue where an InvalidCastException is thrown when importing a document.
Fixed issue where a NullReferenceException is thrown when importing a document with EmbeddedFile without Subtype.
SpeechToTextButton:
Fixed SpeechToTextButton Designer throwing an error at design time.
SpreadProcessing:
SpreadProcessing: XLSX image lock aspect ratio imports incorrectly when importing a document with PictureLockingElement which noChangeAspect attribute is boolean.
XlsFormatProvider: InvalidOperationException is thrown when importing a document with an unsupported BIFF record.
Importing file with comments part with other name than comments.xml throws an exception.
Window:
RadWindow predefined dialogs do not fully expose required accessibility attributes.
WordsProcessing:
PdfFormatProvider: Justified text alignment is not respected for specific text content.