diff --git a/internal/qerr/error_codes.go b/internal/qerr/error_codes.go
index 4ac7cbfea..4158fcdb6 100644
--- a/internal/qerr/error_codes.go
+++ b/internal/qerr/error_codes.go
@@ -20,7 +20,6 @@ const (
 	FinalSizeError          ErrorCode = 0x6
 	FrameEncodingError      ErrorCode = 0x7
 	TransportParameterError ErrorCode = 0x8
-	VersionNegotiationError ErrorCode = 0x9
 	ProtocolViolation       ErrorCode = 0xa
 	CryptoBufferExceeded    ErrorCode = 0xd
 )
@@ -65,8 +64,6 @@ func (e ErrorCode) String() string {
 		return "FRAME_ENCODING_ERROR"
 	case TransportParameterError:
 		return "TRANSPORT_PARAMETER_ERROR"
-	case VersionNegotiationError:
-		return "VERSION_NEGOTIATION_ERROR"
 	case ProtocolViolation:
 		return "PROTOCOL_VIOLATION"
 	case CryptoBufferExceeded: