Migrating to Platform-Agnostic Namespaces

Updated on Aug 4, 2026

Environment

Version	Product	Author
Q3 2026	Document Processing Libraries	Yoan Karamanov

Description

Starting with the Q3 2026 release, the Telerik Document Processing Libraries use platform-agnostic namespaces in both the .NET Framework and .NET Standard package variants. All namespaces no longer contain the word Windows. This is a breaking change that affects any project that references the old Telerik.Windows.Documents.* or Telerik.Windows.Zip namespaces.

This article also answers the following questions:

• Why do my using Telerik.Windows.Documents.* directives no longer resolve after upgrading?
• How do I update my code to use the new namespaces in the Telerik Document Processing Libraries?
• What is the difference between the old and the new namespace naming convention?

Previous State

The Telerik Document Processing Libraries have always been distributed in two package variants:

• .NET Framework packages: These packages target Windows and have the word Windows in their assembly and NuGet package names (for example, Telerik.Windows.Documents.Core, Telerik.Windows.Documents.Fixed).
• .NET Standard packages: These packages are cross-platform and do not contain Windows in their names (for example, Telerik.Documents.Core, Telerik.Documents.Fixed).

Despite this naming difference, both package variants used the same Telerik.Windows.Documents.* namespace hierarchy in most of the classes. This meant that regardless of the package you referenced, all using directives and fully qualified type names had to include the word Windows. For example:

csharp

using Telerik.Windows.Documents.Fixed.Model;
using Telerik.Windows.Documents.Flow.Model;
using Telerik.Windows.Documents.Spreadsheet.Model;

For more details about the two package variants and their differences, see Telerik.Windows.Documents.* vs. Telerik.Documents.*.

Current Change

Starting with Q3 2026, all namespaces in both package variants are now platform-agnostic. The word Windows has been removed from every namespace. The new namespaces align with the naming convention of the .NET Standard packages.

The following table shows examples of how namespaces have changed:

Old namespace	New namespace
Telerik.Windows.Documents.Fixed.Model	Telerik.Documents.Fixed.Model
Telerik.Windows.Documents.Flow.Model	Telerik.Documents.Flow.Model
Telerik.Windows.Documents.Spreadsheet.Model	Telerik.Documents.Spreadsheet.Model
Telerik.Windows.Documents.Core	Telerik.Documents.Core
Telerik.Windows.Documents.Fixed.FormatProviders.Pdf	Telerik.Documents.Fixed.FormatProviders.Pdf
Telerik.Windows.Documents.Flow.FormatProviders.Docx	Telerik.Documents.Flow.FormatProviders.Docx
Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx	Telerik.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx
Telerik.Windows.Zip	Telerik.Zip

The package and assembly names remain unchanged. Only the namespaces have changed. The .NET Framework packages still have Windows in their names (for example, Telerik.Windows.Documents.Core), and the .NET Standard packages still do not (for example, Telerik.Documents.Core).

How This Affects Your Project

Any code that uses the old Telerik.Windows.Documents.* namespaces will produce compiler errors after you upgrade. The errors typically look like this:

error CS0246: The type or namespace name 'Telerik' could not be found
error CS0234: The type or namespace name 'Windows' does not exist in the namespace 'Telerik'

The impact covers:

• All using directives that reference Telerik.Windows.Documents.* and Telerik.Windows.Zip.
• All fully qualified type names in code, such as Telerik.Windows.Documents.Fixed.Model.RadFixedDocument.
• Any string-based type references, such as those in XML configuration or reflection calls.

Solution

To resolve the compiler errors, replace all occurrences of Telerik.Windows.Documents. or Telerik.Windows.Zip with Telerik.Documents. and Telerik.Zip respectively in your source code.

Using Find and Replace

The fastest approach is a project-wide find-and-replace operation:

1. Open your IDE's Find and Replace dialog (Ctrl+H in Visual Studio).
2. Set the search scope to your entire solution or project.
3. Search for Telerik.Windows.Documents. and replace it with Telerik.Documents..
4. Apply the replacement and rebuild the solution.

Updating Using Directives

The following example shows what the updated using directives look like for the most common libraries.

Example 1: Updated Using Directives

csharp

// RadPdfProcessing
using Telerik.Documents.Fixed.Model;
using Telerik.Documents.Fixed.FormatProviders.Pdf;

// RadWordsProcessing
using Telerik.Documents.Flow.Model;
using Telerik.Documents.Flow.FormatProviders.Docx;

// RadSpreadProcessing
using Telerik.Documents.Spreadsheet.Model;
using Telerik.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx;

After the replacement, all type references resolve correctly against both the .NET Framework and .NET Standard package variants.

If your project uses both the .NET Framework and .NET Standard package variants simultaneously, see Resolving Namespace Conflicts in Telerik Document Processing Libraries for guidance on using the extern alias directive.

See Also

• Telerik.Windows.Documents.* vs. Telerik.Documents.* Namespaces
• What Versions of Document Processing Libraries Are Distributed with the Telerik Products
• Resolving Namespace Conflicts in Telerik Document Processing Libraries
• Cross-Platform Support for RadPdfProcessing
• Cross-Platform Support for RadWordsProcessing
• Cross-Platform Support for RadSpreadProcessing
• Available NuGet Packages