Class UnsupportedProtocolVersionException

Namespace

ModelContextProtocol

Assembly

ModelContextProtocol.Core.dll

Represents an exception used to signal that a request's declared protocol version is not supported by the server.

public sealed class UnsupportedProtocolVersionException : McpProtocolException, ISerializable

Inheritance

object

Exception

McpException

McpProtocolException

UnsupportedProtocolVersionException

Implements

ISerializable

Inherited Members

McpProtocolException.ErrorCode

Exception.GetBaseException()

Exception.GetType()

Exception.ToString()

Exception.Data

Exception.HelpLink

Exception.HResult

Exception.InnerException

Exception.Message

Exception.Source

Exception.StackTrace

Exception.TargetSite

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.ReferenceEquals(object, object)

Remarks

Introduced by the 2026-07-28 protocol revision (SEP-2575). Servers throw this exception when they cannot process a request because the per-request _meta/io.modelcontextprotocol/protocolVersion (or the equivalent transport-level header) names a version the server does not implement. The exception is converted to a JSON-RPC error response with code UnsupportedProtocolVersion (-32022) and a UnsupportedProtocolVersionErrorData payload.

Constructors

UnsupportedProtocolVersionException(string, IEnumerable<string>, string?)

Initializes a new instance of the UnsupportedProtocolVersionException class.

public UnsupportedProtocolVersionException(string requested, IEnumerable<string> supported, string? message = null)

Parameters

requested string

The protocol version the client requested.

supported IEnumerable<string>

The protocol versions the server supports.

message string

A human-readable description of the error. If null, a default message is used.

Properties

Requested

Gets the protocol version the client requested.

public string Requested { get; }

Property Value

string

Supported

Gets the protocol versions the server supports.

public IReadOnlyList<string> Supported { get; }

Property Value

IReadOnlyList<string>