diff --git a/sming/sming/commandprocessing/Command.cpp b/sming/sming/commandprocessing/Command.cpp
index 3e7bc4e..3aa98de 100644
--- a/sming/sming/commandprocessing/Command.cpp
+++ b/sming/sming/commandprocessing/Command.cpp
@@ -36,7 +36,6 @@ const String Command::operator[](unsigned int index)
 Command::~Command() {
 	delete cmdVector;
 	delete cmdJsonBuffer;
-	delete &cmdRoot;
 }
 
 JsonObject& Command::getRoot()
@@ -64,7 +63,6 @@ void Command::clear()
 	cmdName = "";
 	delete cmdVector;
 	delete cmdJsonBuffer;
-//	delete cmdRoot;
 	cmdVector = NULL;
 	cmdJsonBuffer = NULL;
 	cmdRoot = NULL;
diff --git a/sming/sming/commandprocessing/CommandOutput.cpp b/sming/sming/commandprocessing/CommandOutput.cpp
index 76fa82e..c0fcfc4 100644
--- a/sming/sming/commandprocessing/CommandOutput.cpp
+++ b/sming/sming/commandprocessing/CommandOutput.cpp
@@ -64,7 +64,6 @@ void CommandOutput::flush()
 		}
 	}
 	outputString = "";
-	delete &cmdRoot;
 	delete cmdJsonBuffer;
 	cmdRoot = NULL;
 	cmdJsonBuffer = NULL;
diff --git a/sming/sming/core/DataSourceStream.h b/sming/sming/core/DataSourceStream.h
index 3df78e9..a496438 100644
--- a/sming/sming/core/DataSourceStream.h
+++ b/sming/sming/core/DataSourceStream.h
@@ -67,6 +67,7 @@ class DelegateStream : public Print, public IDataSourceStream
 	StreamDelegate streamDelegate = NULL;
 	bool finished = false;
 
+	DelegateStream(const DelegateStream&) = delete;
 };
 
 class FlashStream : public Print, public IDataSourceStream
@@ -89,6 +90,8 @@ class FlashStream : public Print, public IDataSourceStream
 	uint32 startAddress = 0;
 	uint32 currentOffset = 0;
 	uint32 streamSize = 0;
+
+	FlashStream(const FlashStream&) = delete;
 };
 
 class MemoryDataStream : public Print, public IDataSourceStream
@@ -113,6 +116,8 @@ class MemoryDataStream : public Print, public IDataSourceStream
 	char* pos;
 	int size;
 	int capacity;
+
+	MemoryDataStream(const MemoryDataStream&) = delete;
 };
 
 class FileStream : public IDataSourceStream
@@ -140,6 +145,8 @@ class FileStream : public IDataSourceStream
 	file_t handle;
 	int pos;
 	int size;
+
+	FileStream(const FileStream&) = delete;
 };
 
 enum TemplateExpandState
@@ -172,6 +179,8 @@ class TemplateFileStream : public FileStream
 	int skipBlockSize;
 	int varDataPos;
 	int varWaitSize;
+
+	TemplateFileStream(const TemplateFileStream&) = delete;
 };
 
 class JsonObjectStream : public MemoryDataStream
@@ -190,6 +199,8 @@ class JsonObjectStream : public MemoryDataStream
 	DynamicJsonBuffer buffer;
 	JsonObject &rootNode;
 	bool send;
+
+	JsonObjectStream(const JsonObjectStream&) = delete;
 };
 
 
diff --git a/sming/sming/network/MqttClient.cpp b/sming/sming/network/MqttClient.cpp
index f84a795..9851a97 100644
--- a/sming/sming/network/MqttClient.cpp
+++ b/sming/sming/network/MqttClient.cpp
@@ -92,12 +92,13 @@ bool MqttClient::publish(String topic, String message, bool retained /* = false*
 
 #define MQTT_COMMAND_MAXSIZE  512 // needs to be relocated
 
-bool MqttClient::publish(String topic, MemoryDataStream reqDataStream, bool retained /* = false */)
+bool MqttClient::publish(String topic, MemoryDataStream& reqDataStream, bool retained /* = false */)
 {
 	char* msgBuffer = new char[MQTT_COMMAND_MAXSIZE+1];
 	int msgSize = reqDataStream.readMemoryBlock(msgBuffer, MQTT_COMMAND_MAXSIZE);
 	msgBuffer[msgSize] = '\0';
 	int res = mqtt_publish(&broker, topic.c_str(), msgBuffer, retained);
+	delete [] msgBuffer;
 	return res > 0;
 }
 
diff --git a/sming/sming/network/MqttClient.h b/sming/sming/network/MqttClient.h
index 61f167c..5e8a560 100644
--- a/sming/sming/network/MqttClient.h
+++ b/sming/sming/network/MqttClient.h
@@ -43,7 +43,7 @@ class MqttClient: protected TcpClient
 	__forceinline TcpClientState getConnectionState() { return TcpClient::getConnectionState(); }
 
 	bool publish(String topic, String message, bool retained = false);
-	bool publish(String topic, MemoryDataStream reqDataStream, bool retained = false);
+	bool publish(String topic, MemoryDataStream& reqDataStream, bool retained = false);
 	bool publishWithQoS(String topic, String message, int QoS, bool retained = false);