diff --git a/chain/blocksync/cbor_gen.go b/chain/blocksync/cbor_gen.go
index 20592c2a3..fbe7145d1 100644
--- a/chain/blocksync/cbor_gen.go
+++ b/chain/blocksync/cbor_gen.go
@@ -7,7 +7,7 @@ import (
 	"io"
 
 	"github.com/filecoin-project/lotus/chain/types"
-	cid "github.com/ipfs/go-cid"
+	"github.com/ipfs/go-cid"
 	cbg "github.com/whyrusleeping/cbor-gen"
 	xerrors "golang.org/x/xerrors"
 )
diff --git a/chain/types/cbor_gen.go b/chain/types/cbor_gen.go
index 018dd7dac..7dca0a2ae 100644
--- a/chain/types/cbor_gen.go
+++ b/chain/types/cbor_gen.go
@@ -9,7 +9,7 @@ import (
 	"github.com/filecoin-project/specs-actors/actors/abi"
 	"github.com/filecoin-project/specs-actors/actors/crypto"
 	"github.com/filecoin-project/specs-actors/actors/runtime/exitcode"
-	cid "github.com/ipfs/go-cid"
+	"github.com/ipfs/go-cid"
 	cbg "github.com/whyrusleeping/cbor-gen"
 	xerrors "golang.org/x/xerrors"
 )
@@ -557,10 +557,21 @@ func (t *Message) MarshalCBOR(w io.Writer) error {
 		_, err := w.Write(cbg.CborNull)
 		return err
 	}
-	if _, err := w.Write([]byte{136}); err != nil {
+	if _, err := w.Write([]byte{137}); err != nil {
 		return err
 	}
 
+	// t.Version (int64) (int64)
+	if t.Version >= 0 {
+		if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajUnsignedInt, uint64(t.Version))); err != nil {
+			return err
+		}
+	} else {
+		if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajNegativeInt, uint64(-t.Version)-1)); err != nil {
+			return err
+		}
+	}
+
 	// t.To (address.Address) (struct)
 	if err := t.To.MarshalCBOR(w); err != nil {
 		return err
@@ -629,10 +640,35 @@ func (t *Message) UnmarshalCBOR(r io.Reader) error {
 		return fmt.Errorf("cbor input should be of type array")
 	}
 
-	if extra != 8 {
+	if extra != 9 {
 		return fmt.Errorf("cbor input had wrong number of fields")
 	}
 
+	// t.Version (int64) (int64)
+	{
+		maj, extra, err := cbg.CborReadHeader(br)
+		var extraI int64
+		if err != nil {
+			return err
+		}
+		switch maj {
+		case cbg.MajUnsignedInt:
+			extraI = int64(extra)
+			if extraI < 0 {
+				return fmt.Errorf("int64 positive overflow")
+			}
+		case cbg.MajNegativeInt:
+			extraI = int64(extra)
+			if extraI < 0 {
+				return fmt.Errorf("int64 negative oveflow")
+			}
+			extraI = -1 - extraI
+		default:
+			return fmt.Errorf("wrong type for int64 field: %d", maj)
+		}
+
+		t.Version = int64(extraI)
+	}
 	// t.To (address.Address) (struct)
 
 	{
diff --git a/chain/types/message.go b/chain/types/message.go
index 3637b2ea8..703c33dfc 100644
--- a/chain/types/message.go
+++ b/chain/types/message.go
@@ -12,6 +12,8 @@ import (
 	"github.com/filecoin-project/go-address"
 )
 
+const MessageVersion = 0
+
 type ChainMsg interface {
 	Cid() cid.Cid
 	VMMessage() *Message
@@ -20,6 +22,8 @@ type ChainMsg interface {
 }
 
 type Message struct {
+	Version int64
+
 	To   address.Address
 	From address.Address
 
@@ -56,6 +60,10 @@ func DecodeMessage(b []byte) (*Message, error) {
 		return nil, err
 	}
 
+	if msg.Version != MessageVersion {
+		return nil, fmt.Errorf("decoded message had incorrect version (%d)", msg.Version)
+	}
+
 	return &msg, nil
 }
 
diff --git a/node/hello/cbor_gen.go b/node/hello/cbor_gen.go
index 7c530a11a..5e0fc5bcd 100644
--- a/node/hello/cbor_gen.go
+++ b/node/hello/cbor_gen.go
@@ -7,7 +7,7 @@ import (
 	"io"
 
 	"github.com/filecoin-project/specs-actors/actors/abi"
-	cid "github.com/ipfs/go-cid"
+	"github.com/ipfs/go-cid"
 	cbg "github.com/whyrusleeping/cbor-gen"
 	xerrors "golang.org/x/xerrors"
 )