C# Version History

Version	.Net Framework	Major Features
C# 1.0	.NET Framework 1.0/1.1	Classes Structs Interfaces Events Properties Delegates Operators and expressions Statements Attributes
C# 2.0	.NET Framework 2.0	Generics Partial types Anonymous methods Nullable value types Iterators Covariance and contravariance
C# 3.0	.NET Framework version 3.5	Auto-implemented properties Anonymous types Query expressions Lambda expressions Expression trees Extension methods Implicitly typed local variables Partial methods Object and collection initializers
C# 4.0	.NET Framework 4.0	Dynamic binding Named/optional arguments Generic covariant and contravariant Embedded interop types
C# 5.0	.NET Framework 4.5	Asynchronous members Caller info attributes
C# 6.0	.NET Framework 4.6	Static imports Exception filters Auto-property initializers Expression bodied members Null propagator String interpolation nameof operator Index initializers Await in catch/finally blocks Default values for getter-only properties
C# 7.0	.NET Core 2.0	Out variables Tuples and deconstruction Pattern matching Local functions Expanded expression bodied members Ref locals and returns Discards Binary Literals and Digit Separators Throw expressions
C# 8.0	.NET Core 3.0	Readonly members Default interface methods Pattern matching enhancements: Switch expressions Property patterns Tuple patterns Positional patterns Using declarations Static local functions Disposable ref structs Nullable reference types Asynchronous streams Indices and ranges Null-coalescing assignment Unmanaged constructed types Stackalloc in nested expressions Enhancement of interpolated verbatim strings
C# 9.0	.NET 5.0	Records Init only setters Top-level statements Pattern matching enhancements Performance and interop Native sized integers Function pointers Suppress emitting localsinit flag Fit and finish features Target-typed new expressions static anonymous functions Target-typed conditional expressions Covariant return types Extension GetEnumerator support for foreach loops Lambda discard parameters Attributes on local functions Support for code generators Module initializers
C#10.0	.NET 6.0	Record structs Improvements of structure types Interpolated string handlers global using directives File-scoped namespace declaration Extended property patterns Improvements on lambda expressions Allow const interpolated strings Record types can seal ToString() Improved definite assignment Allow both assignment and declaration in the same deconstruction Allow AsyncMethodBuilder attribute on methods CallerArgumentExpression attribute Enhanced #line pragma