Languages and Frameworks: C#
JetBrains Rider 2021.2 fully supports all C# versions up to C# 9.0. C# is the primary programming language JetBrains Rider is intended for, and therefore all JetBrains Rider features (excluding some features specific to other languages) are supported in C#.
Change language version
By default, JetBrains Rider automatically detects C# version based on the associated compiler. However, you can specify the target C# version explicitly for a project — press Alt+Enter on the project in the Solution Explorer and use the Language version selector on the Application page of the Project Properties dialog.
To set the C# version for all projects in your solution, specify it in a Directory.Build.props file in your solution directory as described here.
Depending on the current C# version — whether it is detected automatically or set explicitly — JetBrains Rider adjusts its features. For example, code inspection detects places in your code, which could be simplified using new language features.
Information on JetBrains Rider features in C# is available in the following sections: