backwards compatible when no encryption key was added in previous config

machinery/src/models/MQTT.go

@@ -30,7 +30,7 @@ func PackageMQTTMessage(configuration *Configuration, msg Message) ([]byte, erro
 	// At the moment we don't do the encryption part, but we'll implement it
 	// once the legacy methods (subscriptions are moved).
 	msg.Encrypted = false
-	if configuration.Config.Encryption.Enabled {
+	if configuration.Config.Encryption != nil && configuration.Config.Encryption.Enabled {
 		msg.Encrypted = true
 	}
 	msg.PublicKey = ""

machinery/src/routers/mqtt/main.go

@@ -168,7 +168,7 @@ func MQTTListenerHandler(mqttClient mqtt.Client, hubKey string, configDirectory
 				// Messages might be encrypted, if so we'll
 				// need to decrypt them.
 				var payload models.Payload
-				if message.Encrypted {
+				if message.Encrypted && configuration.Config.Encryption != nil && configuration.Config.Encryption.Enabled {
 					encryptedValue := message.Payload.EncryptedValue
 					if len(encryptedValue) > 0 {
 						symmetricKey := configuration.Config.Encryption.SymmetricKey