Telerik UI for ASP.NET AJAX 2026.2.519 (2026 Q2)$$$May 20; 2026$$$$$$Common$$$NEW$$$New SegmentedControl Component$$$Telerik Document Processing Library (DPL) version (2026.2.519)$$$FIXED$$$500 The cryptographic operation has failed when loading combined resource URLs with EnableHandlerEncryption after URL rebuild$$$404 on combined resource URL when EnableHandlerEncryption is enabled — URL exceeds max length due to plaintext length check$$$JS error when hovering a menu after partial postback when a RadButton is in an UpdatePanel and the Telerik.Web.UI.WebResource.axd URL is encrypted$$$The cryptographic operation has failed! error when showing a hidden control and there is RadStyleSheetManager and EnableHandlerEncryption=true$$$AsyncUpload$$$FIXED$$$RadAsyncUpload Drop Files here element remains visible when dragging a file quickly over and out of the DragZone$$$CheckBox$$$FIXED$$$Screen readers announce checked/ not checked when CheckBox feature is disabled$$$ColorPicker$$$FIXED$$$Web palette layout broken - first column misaligned from the rest (Lightweight renderer)$$$Zooming breaks the colorpicker$$$The colorpicker pallet is corrupted in Firefox with different Windows Screen zoom levels$$$DateRangePicker$$$FIXED$$$RadDateRangePicker method set_rangeSelectionStartDate and set_rangeSelectionEndDate not working as expected$$$Editor$$$NEW$$$ImageManager and RadFileExplorer now support .avif; .heif; .heic and .webp file extensions$$$Ability to resize the table columns and rows with the mouse in the content area$$$The StripJavaScriptUris content filter is improved$$$FIXED$$$After pasting from MS Word; StripSpan does not work until a mode change to HTML and back to Design$$$Grid$$$FIXED$$$Scrolling on a mobile (touch) device is impossible with the Lightweight RenderMode when an HTML element takes up the entire grid row$$$The Grids Horizontal scrollbar is not visible in iOS when the grid is empty$$$Input$$$NEW$$$Password textbox with show/hide feature$$$ListBox$$$NEW$$$Allow lazy loading of images with design-time templates$$$Navigation$$$NEW$$$Add Separator feature to the RadNavigation control$$$NumericTextBox$$$FIXED$$$The ShowSpinButtons and Right Alignment cause the number to disappear behind the spinners$$$Rating$$$FIXED$$$Ratings not working with body margin 0$$$TabStrip$$$FIXED$$$The tab text is not being read by the screen reader$$$Accessibility issues - RadTabStrip and RadMultiPageView$$$When keyboard navigation is enabled Tabs keep focus even after focusing other tabs$$$Focus highlighting in TabStrip not working properly with Keyboard Navigation$$$ToggleButton$$$FIXED$$$Icons in RadToggleButton disappear when using ConfirmSettings$$$PdfProcessing$$$NEW$$$Handled import of documents with missing/invalid rectangle (re) operands$$$Handled invalid ASCII85Decode filter scenario - PDF streams where the end-of-data marker contains whitespace$$$Import-export support for ShadingType 1$$$Import-export support for ShadingType 4$$$Import-export support for ShadingType 6$$$Import-export support for ShadingType 7$$$Exposed internal GrayColor object$$$Introduced support for signing multiple Signature fields$$$FIXED$$$? NullReferenceException is thrown when exporting a document with a Type 3 font with missing/invalid Unicode mapping$$$PdfStreamWriter: Duplicated page content due to incorrect caching mechanism$$$PdfStreamWriter: Slow performance during page splitting$$$SkiaImageFormatProvider: NullReferenceException is thrown when exporting pages containing images with missing optional ColorSpace$$$XMP metadata is unescaped during import-export$$$Document password cannot be resolved when document produced by the library contains a SignatureField$$$Hidden PDF layers are imported as visible$$$An Invalid PDF document is exported when inserting a specific Jpeg image with an ICC profile$$$A password is asked although Adobe opens the document without one$$$A CryptographicException because MD5 not available on Blazor WASM$$$Corrupted document when exporting Courier New subset$$$NetStandard: Missing content d

BREAKING CHANGES$$$CSRF validation is now enabled by default for all upload requests. Applications that do not use ASP.NET Session State must add to appSettings. Applications using WebResourceSession handler are not affected. For more information; see CSRF Protection.$$$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.$$$ClientDataSource$$$NEW$$$Added OData v4 transport option.$$$Filter$$$FIXED$$$Replaced Newtonsoft.Json dependency with a built-in serializer for filter expression serialization.$$$DataPager$$$FIXED$$$Fixed field keyword conflict in RadDataPagerDesigner property accessor causing design-time errors.$$$Editor$$$NEW$$$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.$$$Improved keyboard navigation and screen reader support in RadEditor toolbar dropdowns (FontName; FontSize; RealFontSize; ForeColor; BackColor; InsertSymbol; InsertTable etc.).$$$FIXED$$$Design rendering failure with Uncaught TypeError: Cannot read properties of null (reading commonAncestorContainer) when using ToolbarMode=RibbonBarShowOnFocus$$$Keyboard selection 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$$$Fixed HeaderContext filter menu throwing _linkElement undefined error after expand animation ends.$$$NumericTextBox$$$NEW$$$Added EnableMobilePattern property for triggering the numeric keyboard on mobile devices.$$$PdfProcessing$$$NEW$$$Optimized the export of Functions.$$$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.$$$FIXED$$$The import performance is reduced when having XObject instances with many Shading elements.$$$PdfStreamWriter: Merging PDF documents causes blank pages.$$$An InvalidCastException when importing a document.$$$A NullReferenceException is thrown when importing a document with EmbeddedFile without Subtype.$$$SpeechToTextButton$$$FIXED$$$Fixed SpeechToTextButton Designer throwing an error at design time.$$$SpreadProcessing$$$NEW$$$XlsFormatProvider: Add support for hidden rows.$$$Add support for Superscript/Subscript formatting option.$$$Introduced support for notes in XLS format.$$$Add support for Strikethrough formatting option.$$$Introduced support for images when importing and exporting XLS documents.$$$FIXED$$$SpreadProcessing: XLSX image lock aspect ratio imports incorrectly when importing a document with PictureLockingElement which noChangeAspect attribute is boolean$$$XlsFormatProvider: InvalidOperationException is thrown when importing a document with an unsupported BIFF record.$$$Importing file with comments part with other name than comments.xml throws and exception.$$$Window$$$FIXED$$$RadWindow predefined dialogs do not fully expose requ

BREAKING CHANGES$$$CSRF validation is now enabled by default for all upload requests. Applications that do not use ASP.NET Session State must add to appSettings. Applications using WebResourceSession handler are not affected. For more information; see CSRF Protection.$$$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.$$$ClientDataSource$$$NEW$$$Added OData v4 transport option.$$$Filter$$$FIXED$$$Replaced Newtonsoft.Json dependency with a built-in serializer for filter expression serialization.$$$DataPager$$$FIXED$$$Fixed field keyword conflict in RadDataPagerDesigner property accessor causing design-time errors.$$$Editor$$$NEW$$$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.$$$Improved keyboard navigation and screen reader support in RadEditor toolbar dropdowns (FontName; FontSize; RealFontSize; ForeColor; BackColor; InsertSymbol; InsertTable etc.).$$$FIXED$$$Design rendering failure with Uncaught TypeError: Cannot read properties of null (reading commonAncestorContainer) when using ToolbarMode=RibbonBarShowOnFocus$$$Keyboard selection 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$$$Fixed HeaderContext filter menu throwing _linkElement undefined error after expand animation ends.$$$NumericTextBox$$$NEW$$$Added EnableMobilePattern property for triggering the numeric keyboard on mobile devices.$$$PdfProcessing$$$NEW$$$Optimized the export of Functions.$$$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.$$$FIXED$$$The import performance is reduced when having XObject instances with many Shading elements.$$$PdfStreamWriter: Merging PDF documents causes blank pages.$$$An InvalidCastException when importing a document.$$$A NullReferenceException is thrown when importing a document with EmbeddedFile without Subtype.$$$SpeechToTextButton$$$FIXED$$$Fixed SpeechToTextButton Designer throwing an error at design time.$$$SpreadProcessing$$$NEW$$$XlsFormatProvider: Add support for hidden rows.$$$Add support for Superscript/Subscript formatting option.$$$Introduced support for notes in XLS format.$$$Add support for Strikethrough formatting option.$$$Introduced support for images when importing and exporting XLS documents.$$$FIXED$$$SpreadProcessing: XLSX image lock aspect ratio imports incorrectly when importing a document with PictureLockingElement which noChangeAspect attribute is boolean$$$XlsFormatProvider: InvalidOperationException is thrown when importing a document with an unsupported BIFF record.$$$Importing file with comments part with other name than comments.xml throws and exception.$$$Window$$$FIXED$$$RadWindow predefined dialogs do not fully expose requ

BREAKING CHANGES$$$CSRF validation is now enabled by default for all upload requests. Applications that do not use ASP.NET Session State must add to appSettings. Applications using WebResourceSession handler are not affected. For more information; see CSRF Protection.$$$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.$$$ClientDataSource$$$NEW$$$Added OData v4 transport option.$$$Filter$$$FIXED$$$Replaced Newtonsoft.Json dependency with a built-in serializer for filter expression serialization.$$$DataPager$$$FIXED$$$Fixed field keyword conflict in RadDataPagerDesigner property accessor causing design-time errors.$$$Editor$$$NEW$$$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.$$$Improved keyboard navigation and screen reader support in RadEditor toolbar dropdowns (FontName; FontSize; RealFontSize; ForeColor; BackColor; InsertSymbol; InsertTable etc.).$$$FIXED$$$Design rendering failure with Uncaught TypeError: Cannot read properties of null (reading commonAncestorContainer) when using ToolbarMode=RibbonBarShowOnFocus$$$Keyboard selection 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$$$Fixed HeaderContext filter menu throwing _linkElement undefined error after expand animation ends.$$$NumericTextBox$$$NEW$$$Added EnableMobilePattern property for triggering the numeric keyboard on mobile devices.$$$PdfProcessing$$$NEW$$$Optimized the export of Functions.$$$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.$$$FIXED$$$The import performance is reduced when having XObject instances with many Shading elements.$$$PdfStreamWriter: Merging PDF documents causes blank pages.$$$An InvalidCastException when importing a document.$$$A NullReferenceException is thrown when importing a document with EmbeddedFile without Subtype.$$$SpeechToTextButton$$$FIXED$$$Fixed SpeechToTextButton Designer throwing an error at design time.$$$SpreadProcessing$$$NEW$$$XlsFormatProvider: Add support for hidden rows.$$$Add support for Superscript/Subscript formatting option.$$$Introduced support for notes in XLS format.$$$Add support for Strikethrough formatting option.$$$Introduced support for images when importing and exporting XLS documents.$$$FIXED$$$SpreadProcessing: XLSX image lock aspect ratio imports incorrectly when importing a document with PictureLockingElement which noChangeAspect attribute is boolean$$$XlsFormatProvider: InvalidOperationException is thrown when importing a document with an unsupported BIFF record.$$$Importing file with comments part with other name than comments.xml throws and exception.$$$Window$$$FIXED$$$RadWindow predefined dialogs do not fully expose requ

Telerik UI for ASP.NET AJAX 2026.1.225$$$February 25; 2026$$$$$$Security$$$FIXED$$$Addressed CVE-2026-2878$$$External jQuery scripts are now loaded through a Telerik Handler that ensures correct load order and restricts sources to trusted CDN hosts$$$Common$$$FIXED$$$ReferenceError: kendo is not defined in version 2026 Q1$$$Editor$$$FIXED$$$Duplicate toolbars rendered when ToolProviderID is used with programmatically added Tools$$$Gantt$$$FIXED$$$RadGantt throws: Uncaught ReferenceError: kendo is not defined$$$HtmlChart$$$FIXED$$$The HtmlChart throws: Uncaught ReferenceError: kendo is not defined$$$Uncaught TypeError: Cannot read properties of undefined (reading toLowerCase)$$$SearchBox$$$FIXED$$$Fixed the EnableAriaSupport ClientPropertyName mismatch$$$SmartPasteButton$$$NEW$$$Added Visual Studio Designer support for RadSmartPasteButton$$$Added RenderMode support for RadSmartPasteButton$$$Spreadsheet$$$FIXED$$$Spreadsheet throws: Uncaught ReferenceError: kendo is not defined

Telerik UI for ASP.NET AJAX 2026.1.225$$$February 25; 2026$$$$$$Security$$$FIXED$$$Addressed CVE-2026-2878$$$External jQuery scripts are now loaded through a Telerik Handler that ensures correct load order and restricts sources to trusted CDN hosts$$$Common$$$FIXED$$$ReferenceError: kendo is not defined in version 2026 Q1$$$Editor$$$FIXED$$$Duplicate toolbars rendered when ToolProviderID is used with programmatically added Tools$$$Gantt$$$FIXED$$$RadGantt throws: Uncaught ReferenceError: kendo is not defined$$$HtmlChart$$$FIXED$$$The HtmlChart throws: Uncaught ReferenceError: kendo is not defined$$$Uncaught TypeError: Cannot read properties of undefined (reading toLowerCase)$$$SearchBox$$$FIXED$$$Fixed the EnableAriaSupport ClientPropertyName mismatch$$$SmartPasteButton$$$NEW$$$Added Visual Studio Designer support for RadSmartPasteButton$$$Added RenderMode support for RadSmartPasteButton$$$Spreadsheet$$$FIXED$$$Spreadsheet throws: Uncaught ReferenceError: kendo is not defined