diff --git a/cmd/strom/mca_to_tmcpr/main.go b/cmd/strom/mca_to_tmcpr/main.go
index 94d04c4..39c296b 100644
--- a/cmd/strom/mca_to_tmcpr/main.go
+++ b/cmd/strom/mca_to_tmcpr/main.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log/slog"
 	"os"
+	"path/filepath"
 
 	"github.com/admin-else/strom/mc/level"
 	"github.com/admin-else/strom/mc/level/anvil"
@@ -51,7 +52,7 @@ func GetChunkFromMca(x, z int32, version string) (b []byte, err error) {
 		z += anvil.ChunksWidthRegionFile
 	}
 
-	f, err := os.Open(fmt.Sprintf("./.devres/anvil_testdata/securechattestworld/region/r.%v.%v.mca", xmca, zmca))
+	f, err := os.Open(filepath.Join(*worldPath, "region", fmt.Sprintf("r.%v.%v.mca", xmca, zmca)))
 	if err != nil {
 		return
 	}
diff --git a/cmd/strom/raw_to_tmcpr/main.go b/cmd/strom/raw_to_tmcpr/main.go
index bf0aaa9..6e4a63f 100644
--- a/cmd/strom/raw_to_tmcpr/main.go
+++ b/cmd/strom/raw_to_tmcpr/main.go
@@ -20,8 +20,9 @@ var ClientboundIn = Cmd.String("clientbound", "", "raw tcpflow file for clientbo
 var ServerboundIn = Cmd.String("serverbound", "", "raw tcpflow file for serverbound (client->server) direction")
 var ClientboundOut = Cmd.String("clientbound-out", "clientbound.tmcpr", "output TMCPR file for clientbound")
 var ServerboundOut = Cmd.String("serverbound-out", "serverbound.tmcpr", "output TMCPR file for serverbound")
-var ClientboundState = Cmd.String("clientbound-state", "login", "initial state for clientbound: handshake, login, status, play")
-var ServerboundState = Cmd.String("serverbound-state", "handshake", "initial state for serverbound: handshake, login, status, play")
+var ClientboundState = Cmd.String("clientbound-state", "login", "initial state for clientbound: handshake, login, config, status, play")
+var ServerboundState = Cmd.String("serverbound-state", "handshake", "initial state for serverbound: handshake, login, config, status, play")
+var UseConfig = Cmd.Bool("config", false, "use Configuration state transitions (for protocol >= 764, Minecraft 1.20.2+)")
 
 type captureReader struct {
 	r              io.Reader
@@ -32,6 +33,7 @@ type captureReader struct {
 	haveStartTime  bool
 	direction      proto_base.Direction
 	pendingThreshold int32
+	useConfig      bool
 }
 
 func (cr *captureReader) setStartTime() {
@@ -123,13 +125,21 @@ func (cr *captureReader) trackState(packetBytes []byte) {
 					cr.threshold = threshold
 				}
 			} else if packetId == 0x02 {
-				cr.state = proto_base.Play
+				if cr.useConfig {
+					cr.state = proto_base.Configuration
+				} else {
+					cr.state = proto_base.Play
+				}
 			}
 		} else if cr.direction == proto_base.ToServer && packetId == 0 {
 			if cr.pendingThreshold >= 0 {
 				cr.threshold = cr.pendingThreshold
 			}
 		}
+	case proto_base.Configuration:
+		if cr.direction == proto_base.ToClient && packetId == 0x02 {
+			cr.state = proto_base.Play
+		}
 	case proto_base.Status:
 	case proto_base.Play:
 	}
@@ -172,12 +182,14 @@ func Run(args []string) (err error) {
 			return proto_base.Handshaking, nil
 		case "login":
 			return proto_base.Login, nil
+		case "config":
+			return proto_base.Configuration, nil
 		case "play":
 			return proto_base.Play, nil
 		case "status":
 			return proto_base.Status, nil
 		default:
-			return 0, fmt.Errorf("unknown state: %s (valid: handshake, login, status, play)", name)
+			return 0, fmt.Errorf("unknown state: %s (valid: handshake, login, config, status, play)", name)
 		}
 	}
 
@@ -188,7 +200,7 @@ func Run(args []string) (err error) {
 		if err != nil {
 			return err
 		}
-		compressionThreshold, err = processFile(*ClientboundIn, *ClientboundOut, state, proto_base.ToClient, -1)
+		compressionThreshold, err = processFile(*ClientboundIn, *ClientboundOut, state, proto_base.ToClient, -1, *UseConfig)
 		if err != nil {
 			return fmt.Errorf("clientbound: %w", err)
 		}
@@ -199,7 +211,7 @@ func Run(args []string) (err error) {
 		if err != nil {
 			return err
 		}
-		_, err = processFile(*ServerboundIn, *ServerboundOut, state, proto_base.ToServer, compressionThreshold)
+		_, err = processFile(*ServerboundIn, *ServerboundOut, state, proto_base.ToServer, compressionThreshold, *UseConfig)
 		if err != nil {
 			return fmt.Errorf("serverbound: %w", err)
 		}
@@ -208,7 +220,7 @@ func Run(args []string) (err error) {
 	return
 }
 
-func processFile(inPath, outPath string, initial proto_base.State, dir proto_base.Direction, initialThreshold int32) (finalThreshold int32, err error) {
+func processFile(inPath, outPath string, initial proto_base.State, dir proto_base.Direction, initialThreshold int32, useConfig bool) (finalThreshold int32, err error) {
 	in, err := os.Open(inPath)
 	if err != nil {
 		return initialThreshold, fmt.Errorf("open input: %w", err)
@@ -228,6 +240,7 @@ func processFile(inPath, outPath string, initial proto_base.State, dir proto_bas
 		threshold: -1,
 		direction: dir,
 		pendingThreshold: initialThreshold,
+		useConfig: useConfig,
 	}
 	if dir == proto_base.ToClient {
 		cr.threshold = initialThreshold
diff --git a/mc/proto/multiversion_test.go b/mc/proto/multiversion_test.go
new file mode 100644
index 0000000..877d0b9
--- /dev/null
+++ b/mc/proto/multiversion_test.go
@@ -0,0 +1,160 @@
+package proto_test
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/admin-else/strom/mc/data"
+	"github.com/admin-else/strom/mc/proto"
+	"github.com/admin-else/strom/mc/proto_base"
+	"github.com/admin-else/strom/mc/proto_generated"
+)
+
+func TestPacketRoundTripAllVersions(t *testing.T) {
+	results := map[string][4]int{}
+	for _, version := range proto_generated.SupportedVersions {
+		protoVer := data.MustLookupProtocolVersion(version)
+		total, encFailed, decFailed, ok := 0, 0, 0, 0
+		for _, pin := range proto_generated.Packets {
+			if pin.ProtocolVersion != int32(protoVer) {
+				continue
+			}
+			total++
+			b, err := proto.SimplePacketToBytes(pin.Type)
+			if err != nil {
+				if err == proto_base.ToDoError || strings.Contains(err.Error(), "unsupported") || strings.Contains(err.Error(), "index not found") || strings.Contains(err.Error(), "bad type") {
+					encFailed++
+					continue
+				}
+				t.Errorf("%s/%s: encode error: %v", version, pin.Name, err)
+				continue
+			}
+			decoded, err := proto.SimpleBytesToPacket(b, int32(protoVer), pin.Direction, pin.State)
+			if err != nil {
+				t.Errorf("%s/%s: decode error: %v", version, pin.Name, err)
+				continue
+			}
+			if unc, ok := decoded.(*proto.UnCodablePacket); ok {
+				if unc.Err == proto_base.ToDoError {
+					decFailed++
+					continue
+				}
+				t.Errorf("%s/%s: uncodable: %v", version, pin.Name, unc.Err)
+				continue
+			}
+			b2, err := proto.SimplePacketToBytes(decoded)
+			if err != nil {
+				t.Errorf("%s/%s: re-encode error: %v", version, pin.Name, err)
+				continue
+			}
+			if len(b) != len(b2) {
+				t.Errorf("%s/%s: byte length mismatch %d != %d", version, pin.Name, len(b), len(b2))
+			}
+			ok++
+		}
+		results[version] = [4]int{total, encFailed, decFailed, ok}
+	}
+	fmt.Println()
+	for _, version := range proto_generated.SupportedVersions {
+		r := results[version]
+		fmt.Printf("%-8s %3d pkt  enc-skip:%-3d  dec-skip:%-3d  ok:%-3d\n", version, r[0], r[1], r[2], r[3])
+	}
+}
+
+func TestSmartConvertCheck(t *testing.T) {
+	panicCount := 0
+	notConvertible := 0
+	convertible := 0
+	totalPairs := 0
+	for _, fromV := range proto_generated.SupportedVersions {
+		for _, toV := range proto_generated.SupportedVersions {
+			if fromV == toV {
+				continue
+			}
+			fromVer := data.MustLookupProtocolVersion(fromV)
+			toVer := data.MustLookupProtocolVersion(toV)
+			for _, pinFrom := range proto_generated.Packets {
+				if pinFrom.ProtocolVersion != int32(fromVer) {
+					continue
+				}
+				pinTo, found := proto.LookupPacketInfoByNameProtocolVersionStateAndDirection(
+					pinFrom.Name, int32(toVer), pinFrom.State, pinFrom.Direction,
+				)
+				if !found {
+					continue
+				}
+				totalPairs++
+				func() {
+					defer func() {
+						if r := recover(); r != nil {
+							panicCount++
+						}
+					}()
+					fromT := typeInfo(pinFrom.Type)
+					toT := typeInfo(pinTo.Type)
+					if proto.SmartConvertibleTo(fromT, toT) {
+						convertible++
+					} else {
+						notConvertible++
+					}
+				}()
+			}
+		}
+	}
+	fmt.Printf("smart convert: %d pairs, %d convertible, %d not, %d panics\n", totalPairs, convertible, notConvertible, panicCount)
+}
+
+func typeInfo(t proto_base.EncodeDecodeAble) reflect.Type {
+	rt := reflect.TypeOf(t)
+	for rt.Kind() == reflect.Ptr {
+		rt = rt.Elem()
+	}
+	return rt
+}
+
+func TestCrossVersionDecode(t *testing.T) {
+	errors := 0
+	panics := 0
+	total := 0
+	for _, toV := range proto_generated.SupportedVersions {
+		toVer := data.MustLookupProtocolVersion(toV)
+		for _, pin := range proto_generated.Packets {
+			if pin.ProtocolVersion == int32(toVer) {
+				continue
+			}
+			_, found := proto.LookupPacketInfoByNameProtocolVersionStateAndDirection(
+				pin.Name, int32(toVer), pin.State, pin.Direction,
+			)
+			if !found {
+				continue
+			}
+			b, err := proto.SimplePacketToBytes(pin.Type)
+			if err != nil {
+				continue
+			}
+			total++
+			func() {
+				defer func() {
+					if r := recover(); r != nil {
+						panics++
+					}
+				}()
+				decoded, err := proto.SimpleBytesToPacket(b, int32(toVer), pin.Direction, pin.State)
+				if err != nil {
+					errors++
+					return
+				}
+				if _, ok := decoded.(*proto.UnCodablePacket); ok {
+					return
+				}
+				_, err = proto.SimplePacketToBytes(decoded)
+				if err != nil {
+					errors++
+				}
+			}()
+		}
+	}
+	fmt.Printf("cross-version decode: %d attempts, %d errors, %d panics\n", total, errors, panics)
+}