diff --git a/config.go b/config.go
index b22cbf2f9..fdb4344dd 100644
--- a/config.go
+++ b/config.go
@@ -328,6 +328,8 @@ type config struct {
 	WtClient *lncfg.WtClient `group:"wtclient" namespace:"wtclient"`
 
 	Watchtower *lncfg.Watchtower `group:"watchtower" namespace:"watchtower"`
+
+	LegacyProtocol *lncfg.LegacyProtocol `group:"legacyprotocol" namespace:"legacyprotocol"`
 }
 
 // loadConfig initializes and parses the config using a config file and command
diff --git a/lncfg/protocol_legacy_off.go b/lncfg/protocol_legacy_off.go
new file mode 100644
index 000000000..6f5660e9a
--- /dev/null
+++ b/lncfg/protocol_legacy_off.go
@@ -0,0 +1,16 @@
+// +build !dev
+
+package lncfg
+
+// LegacyProtocol is a struct that we use to be able to test backwards
+// compatibility of protocol additions, while defaulting to the latest within
+// lnd.
+type LegacyProtocol struct {
+}
+
+// LegacyOnion returns true if the old legacy onion format should be used when
+// we're an intermediate or final hop. This controls if we set the
+// TLVOnionPayloadOptional bit or not.
+func (l *LegacyProtocol) LegacyOnion() bool {
+	return false
+}
diff --git a/lncfg/protocol_legacy_on.go b/lncfg/protocol_legacy_on.go
new file mode 100644
index 000000000..52bd93880
--- /dev/null
+++ b/lncfg/protocol_legacy_on.go
@@ -0,0 +1,20 @@
+// +build dev
+
+package lncfg
+
+// LegacyProtocol is a struct that we use to be able to test backwards
+// compatibility of protocol additions, while defaulting to the latest within
+// lnd.
+type LegacyProtocol struct {
+	// Onion if set to true, then we won't signal TLVOnionPayloadOptional.
+	// As a result, nodes that include us in the route won't use the new
+	// modern onion framing.
+	Onion bool `long:"onion" description:"force node to not advertise the new modern TLV onion format"`
+}
+
+// LegacyOnion returns true if the old legacy onion format should be used when
+// we're an intermediate or final hop. This controls if we set the
+// TLVOnionPayloadOptional bit or not.
+func (l *LegacyProtocol) LegacyOnion() bool {
+	return l.Onion
+}
diff --git a/server.go b/server.go
index d1b89ccda..7a37e7695 100644
--- a/server.go
+++ b/server.go
@@ -312,7 +312,12 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB,
 	}
 
 	globalFeatures := lnwire.NewRawFeatureVector()
-	globalFeatures.Set(lnwire.TLVOnionPayloadOptional)
+
+	// Only if we're not being forced to use the legacy onion format, will
+	// we signal our knowledge of the new TLV onion format.
+	if !cfg.LegacyProtocol.LegacyOnion() {
+		globalFeatures.Set(lnwire.TLVOnionPayloadOptional)
+	}
 
 	var serializedPubKey [33]byte
 	copy(serializedPubKey[:], privKey.PubKey().SerializeCompressed())