{"record":{"id":"f9d72b09755dd9f1","repo":"XTLS/Xray-core","slug":"unexpected-response-version-expecting-d-but-actu","errorCode":null,"errorMessage":"unexpected response version. Expecting %d but actually %d","messagePattern":"unexpected response version\\. Expecting (.+?) but actually (.+?)","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"proxy/vless/encoding/encoding.go","lineNumber":164,"sourceCode":"\n\tif _, err := writer.Write(buffer.Bytes()); err != nil {\n\t\treturn errors.New(\"failed to write response header\").Base(err)\n\t}\n\n\treturn nil\n}\n\n// DecodeResponseHeader decodes and returns (if successful) a ResponseHeader from an input stream.\nfunc DecodeResponseHeader(reader io.Reader, request *protocol.RequestHeader) (*Addons, error) {\n\tbuffer := buf.StackNew()\n\tdefer buffer.Release()\n\n\tif _, err := buffer.ReadFullFrom(reader, 1); err != nil {\n\t\treturn nil, errors.New(\"failed to read response version\").Base(err)\n\t}\n\n\tif buffer.Byte(0) != request.Version {\n\t\treturn nil, errors.New(\"unexpected response version. Expecting \", int(request.Version), \" but actually \", int(buffer.Byte(0)))\n\t}\n\n\tresponseAddons, err := DecodeHeaderAddons(&buffer, reader)\n\tif err != nil {\n\t\treturn nil, errors.New(\"failed to decode response header addons\").Base(err)\n\t}\n\n\treturn responseAddons, nil\n}\n\n// XtlsRead can switch to splice copy\nfunc XtlsRead(reader buf.Reader, writer buf.Writer, timer *signal.ActivityTimer, conn net.Conn, trafficState *proxy.TrafficState, isUplink bool, ctx context.Context) error {\n\terr := func() error {\n\t\tfor {\n\t\t\tif isUplink && trafficState.Inbound.UplinkReaderDirectCopy || !isUplink && trafficState.Outbound.DownlinkReaderDirectCopy {\n\t\t\t\tvar writerConn net.Conn\n\t\t\t\tvar inTimer *signal.ActivityTimer\n\t\t\t\tif inbound := session.InboundFromContext(ctx); inbound != nil && inbound.Conn != nil {","sourceCodeStart":146,"sourceCodeEnd":182,"githubUrl":"https://github.com/XTLS/Xray-core/blob/7d214f8b094f75322fa3990f8aadad1c912f24f5/proxy/vless/encoding/encoding.go#L146-L182","documentation":"Error \"unexpected response version. Expecting %d but actually %d\" thrown in XTLS/Xray-core.","triggerScenarios":"Thrown at proxy/vless/encoding/encoding.go:164 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"7d214f8b094f75322fa3990f8aadad1c912f24f5","analyzedAt":"2026-08-15T14:26:24.325Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}