diff --git a/crypto/proof_rsa.go b/crypto/proof_rsa.go
index a580d298c..de83b1a70 100644
--- a/crypto/proof_rsa.go
+++ b/crypto/proof_rsa.go
@@ -44,10 +44,15 @@ func LoadKeyData(certFileName string, keyFileName string) (*KeyData, error) {
 // SignServerProof signs CHLO and server config for use in the server proof
 func (kd *KeyData) SignServerProof(chlo []byte, serverConfigData []byte) ([]byte, error) {
 	hash := sha256.New()
-	hash.Write([]byte("QUIC CHLO and server config signature\x00"))
-	chloHash := sha256.Sum256(chlo)
-	hash.Write([]byte{32, 0, 0, 0})
-	hash.Write(chloHash[:])
+	if len(chlo) > 0 {
+		// Version >= 31
+		hash.Write([]byte("QUIC CHLO and server config signature\x00"))
+		chloHash := sha256.Sum256(chlo)
+		hash.Write([]byte{32, 0, 0, 0})
+		hash.Write(chloHash[:])
+	} else {
+		hash.Write([]byte("QUIC server config signature\x00"))
+	}
 	hash.Write(serverConfigData)
 	return rsa.SignPSS(rand.Reader, kd.key, crypto.SHA256, hash.Sum(nil), &rsa.PSSOptions{SaltLength: 32})
 }
diff --git a/example/main.go b/example/main.go
index 609796888..b84b8d349 100644
--- a/example/main.go
+++ b/example/main.go
@@ -15,6 +15,11 @@ import (
 	"github.com/lucas-clemente/quic-go/utils"
 )
 
+var supportedVersions = map[protocol.VersionNumber]bool{
+	30: true,
+	32: true,
+}
+
 func main() {
 	path := os.Getenv("GOPATH") + "/src/github.com/lucas-clemente/quic-go/example/"
 	keyData, err := crypto.LoadKeyData(path+"cert.der", path+"key.der")
@@ -55,7 +60,7 @@ func main() {
 		fmt.Printf("Got packet # %d\n", publicHeader.PacketNumber)
 
 		// Send Version Negotiation Packet if the client is speaking a different protocol version
-		if publicHeader.VersionFlag && publicHeader.VersionNumber != 32 {
+		if publicHeader.VersionFlag && !supportedVersions[publicHeader.VersionNumber] {
 			fmt.Println("Sending VersionNegotiationPacket")
 			fullReply := &bytes.Buffer{}
 			responsePublicHeader := quic.PublicHeader{ConnectionID: publicHeader.ConnectionID, PacketNumber: 1, VersionFlag: true}
@@ -63,6 +68,7 @@ func main() {
 			if err != nil {
 				panic(err)
 			}
+			// TODO: Send all versions
 			utils.WriteUint32(fullReply, protocol.VersionNumberToTag(protocol.VersionNumber(32)))
 			_, err = conn.WriteToUDP(fullReply.Bytes(), remoteAddr)
 			if err != nil {
@@ -73,7 +79,7 @@ func main() {
 
 		session, ok := sessions[publicHeader.ConnectionID]
 		if !ok {
-			session = quic.NewSession(conn, publicHeader.ConnectionID, serverConfig, handleStream)
+			session = quic.NewSession(conn, publicHeader.VersionNumber, publicHeader.ConnectionID, serverConfig, handleStream)
 			sessions[publicHeader.ConnectionID] = session
 		}
 		err = session.HandlePacket(remoteAddr, data[0:n-r.Len()], publicHeader, r)
diff --git a/session.go b/session.go
index 82bae67ec..9a0e9e19f 100644
--- a/session.go
+++ b/session.go
@@ -16,8 +16,9 @@ type StreamCallback func(*StreamFrame) []Frame
 
 // A Session is a QUIC session
 type Session struct {
-	ConnectionID protocol.ConnectionID
-	ServerConfig *ServerConfig
+	VersionNumber protocol.VersionNumber
+	ConnectionID  protocol.ConnectionID
+	ServerConfig  *ServerConfig
 
 	Connection        *net.UDPConn
 	CurrentRemoteAddr *net.UDPAddr
@@ -32,9 +33,10 @@ type Session struct {
 }
 
 // NewSession makes a new session
-func NewSession(conn *net.UDPConn, connectionID protocol.ConnectionID, sCfg *ServerConfig, streamCallback StreamCallback) *Session {
+func NewSession(conn *net.UDPConn, v protocol.VersionNumber, connectionID protocol.ConnectionID, sCfg *ServerConfig, streamCallback StreamCallback) *Session {
 	return &Session{
 		Connection:     conn,
+		VersionNumber:  v,
 		ConnectionID:   connectionID,
 		ServerConfig:   sCfg,
 		aead:           &crypto.NullAEAD{},
@@ -172,7 +174,11 @@ func (s *Session) HandleCryptoHandshake(frame *StreamFrame) error {
 		return nil
 	}
 
-	proof, err := s.ServerConfig.Sign(frame.Data)
+	var chloOrNil []byte
+	if s.VersionNumber > protocol.VersionNumber(30) {
+		chloOrNil = frame.Data
+	}
+	proof, err := s.ServerConfig.Sign(chloOrNil)
 	if err != nil {
 		return err
 	}