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What's new in C# 13

• 05/29/2025

C# 13 includes the following new features. You can try these features using the latest Visual Studio 2022 version or the .NET 9 SDK:

• params collections
• New lock type and semantics.
• New escape sequence - \e.
• Method group natural type improvements
• Implicit indexer access in object initializers
• Enable ref locals and unsafe contexts in iterators and async methods
• Enable ref struct types to implement interfaces.
• Allow ref struct types as arguments for type parameters in generics.
• Partial properties and indexers are now allowed in partial types.
• Overload resolution priority allows library authors to designate one overload as better than others.

Beginning with Visual Studio 17.12, C# 13 includes the field contextual keyword as a preview feature.

C# 13 is supported on .NET 9. For more information, see C# language versioning.

You can download the latest .NET 9 SDK from the .NET downloads page. You can also download Visual Studio 2022, which includes the .NET 9 SDK.

You can find any breaking changes introduced in C# 13 in our article on breaking changes.