diff --git a/MongoDB/include/Poco/MongoDB/Array.h b/MongoDB/include/Poco/MongoDB/Array.h
index a3bf7f27f8..5f6fcbadeb 100644
--- a/MongoDB/include/Poco/MongoDB/Array.h
+++ b/MongoDB/include/Poco/MongoDB/Array.h
@@ -36,7 +36,7 @@ class MongoDB_API Array: public Document
 	Array();
 		/// Creates an empty Array.
 
-	virtual ~Array();
+	~Array() override;
 		/// Destroys the Array.
 
 	// Document template functions available for backward compatibility
@@ -93,7 +93,7 @@ class MongoDB_API Array: public Document
 		return Document::isType<T>(Poco::NumberFormatter::format(pos));
 	}
 
-	std::string toString(int indent = 0) const;
+	std::string toString(int indent = 0) const override;
 		/// Returns a string representation of the Array.
 
 private:
diff --git a/MongoDB/include/Poco/MongoDB/Binary.h b/MongoDB/include/Poco/MongoDB/Binary.h
index 5e9eb58f20..9563b1b26f 100644
--- a/MongoDB/include/Poco/MongoDB/Binary.h
+++ b/MongoDB/include/Poco/MongoDB/Binary.h
@@ -20,12 +20,8 @@
 
 #include "Poco/MongoDB/MongoDB.h"
 #include "Poco/MongoDB/Element.h"
-#include "Poco/Base64Encoder.h"
 #include "Poco/Buffer.h"
-#include "Poco/StreamCopier.h"
-#include "Poco/MemoryStream.h"
 #include "Poco/UUID.h"
-#include <sstream>
 
 
 namespace Poco {
@@ -106,7 +102,7 @@ inline Buffer<unsigned char>& Binary::buffer()
 
 inline std::string Binary::toRawString() const
 {
-	return std::string(reinterpret_cast<const char*>(_buffer.begin()), _buffer.size());
+	return {reinterpret_cast<const char*>(_buffer.begin()), _buffer.size()};
 }
 
 
@@ -145,7 +141,7 @@ inline void BSONWriter::write<Binary::Ptr>(Binary::Ptr& from)
 {
 	_writer << (Poco::Int32) from->buffer().size();
 	_writer << from->subtype();
-	_writer.writeRaw((char*) from->buffer().begin(), from->buffer().size());
+	_writer.writeRaw(reinterpret_cast<char*>(from->buffer().begin()), from->buffer().size());
 }
 
 
diff --git a/MongoDB/include/Poco/MongoDB/Connection.h b/MongoDB/include/Poco/MongoDB/Connection.h
index 5b718fa5a0..85d0616c52 100644
--- a/MongoDB/include/Poco/MongoDB/Connection.h
+++ b/MongoDB/include/Poco/MongoDB/Connection.h
@@ -20,7 +20,6 @@
 
 #include "Poco/Net/SocketAddress.h"
 #include "Poco/Net/StreamSocket.h"
-#include "Poco/Mutex.h"
 #include "Poco/MongoDB/RequestMessage.h"
 #include "Poco/MongoDB/ResponseMessage.h"
 #include "Poco/MongoDB/OpMsgMessage.h"
diff --git a/MongoDB/include/Poco/MongoDB/Document.h b/MongoDB/include/Poco/MongoDB/Document.h
index f84fc122d0..ad33af5a30 100644
--- a/MongoDB/include/Poco/MongoDB/Document.h
+++ b/MongoDB/include/Poco/MongoDB/Document.h
@@ -108,7 +108,7 @@ class MongoDB_API Document
 		/// Returns true if the document has an element with the given name.
 
 	template<typename T>
-	T get(const std::string& name) const
+	const T& get(const std::string& name) const
 		/// Returns the element with the given name and tries to convert
 		/// it to the template type. When the element is not found, a
 		/// NotFoundException will be thrown. When the element can't be
@@ -123,7 +123,7 @@ class MongoDB_API Document
 		{
 			if (ElementTraits<T>::TypeId == element->type())
 			{
-				ConcreteElement<T>* concrete = dynamic_cast<ConcreteElement<T>* >(element.get());
+				auto* concrete = dynamic_cast<ConcreteElement<T>* >(element.get());
 				if (concrete != 0)
 				{
 					return concrete->value();
@@ -134,7 +134,7 @@ class MongoDB_API Document
 	}
 
 	template<typename T>
-	T get(const std::string& name, const T& def) const
+	const T& get(const std::string& name, const T& def) const
 		/// Returns the element with the given name and tries to convert
 		/// it to the template type. When the element is not found, or
 		/// has the wrong type, the def argument will be returned.
@@ -147,7 +147,7 @@ class MongoDB_API Document
 
 		if (ElementTraits<T>::TypeId == element->type())
 		{
-			ConcreteElement<T>* concrete = dynamic_cast<ConcreteElement<T>* >(element.get());
+			auto* concrete = dynamic_cast<ConcreteElement<T>* >(element.get());
 			if (concrete != 0)
 			{
 				return concrete->value();
@@ -232,9 +232,9 @@ inline bool Document::empty() const
 
 inline void Document::elementNames(std::vector<std::string>& keys) const
 {
-	for (ElementSet::const_iterator it = _elements.begin(); it != _elements.end(); ++it)
+	for (const auto & _element : _elements)
 	{
-		keys.push_back((*it)->name());
+		keys.push_back(_element->name());
 	}
 }
 
diff --git a/MongoDB/include/Poco/MongoDB/Element.h b/MongoDB/include/Poco/MongoDB/Element.h
index 47a9fae7e1..78e845be8f 100644
--- a/MongoDB/include/Poco/MongoDB/Element.h
+++ b/MongoDB/include/Poco/MongoDB/Element.h
@@ -25,7 +25,6 @@
 #include "Poco/Nullable.h"
 #include "Poco/NumberFormatter.h"
 #include "Poco/DateTimeFormatter.h"
-#include "Poco/UTF8String.h"
 #include "Poco/MongoDB/MongoDB.h"
 #include "Poco/MongoDB/BSONReader.h"
 #include "Poco/MongoDB/BSONWriter.h"
@@ -115,9 +114,9 @@ struct ElementTraits<std::string>
 
 		oss << '"';
 
-		for (std::string::const_iterator it = value.begin(); it != value.end(); ++it)
+		for (char it : value)
 		{
-			switch (*it)
+			switch (it)
 			{
 			case '"':
 				oss << "\\\"";
@@ -142,13 +141,13 @@ struct ElementTraits<std::string>
 				break;
 			default:
 				{
-					if ( *it > 0 && *it <= 0x1F )
+					if ( it > 0 && it <= 0x1F )
 					{
-						oss << "\\u" << std::hex << std::uppercase << std::setfill('0') << std::setw(4) << static_cast<int>(*it);
+						oss << "\\u" << std::hex << std::uppercase << std::setfill('0') << std::setw(4) << static_cast<int>(it);
 					}
 					else
 					{
-						oss << *it;
+						oss << it;
 					}
 					break;
 				}
@@ -360,34 +359,32 @@ class ConcreteElement: public Element
 	{
 	}
 
-	virtual ~ConcreteElement()
-	{
-	}
+	~ConcreteElement() override = default;
 
 
-	T value() const
+	const T& value() const
 	{
 		return _value;
 	}
 
 
-	std::string toString(int indent = 0) const
+	std::string toString(int indent = 0) const override
 	{
 		return ElementTraits<T>::toString(_value, indent);
 	}
 
 
-	int type() const
+	int type() const override
 	{
 		return ElementTraits<T>::TypeId;
 	}
 
-	void read(BinaryReader& reader)
+	void read(BinaryReader& reader) override
 	{
 		BSONReader(reader).read(_value);
 	}
 
-	void write(BinaryWriter& writer)
+	void write(BinaryWriter& writer) override
 	{
 		BSONWriter(writer).write(_value);
 	}
diff --git a/MongoDB/src/Array.cpp b/MongoDB/src/Array.cpp
index 6fff0994d8..c4e4b6b6de 100644
--- a/MongoDB/src/Array.cpp
+++ b/MongoDB/src/Array.cpp
@@ -46,7 +46,7 @@ std::string Array::toString(int indent) const
 
 	if (indent > 0) oss << std::endl;
 
-	for (ElementSet::const_iterator it = _elements.begin(); it != _elements.end(); ++it)
+	for (auto it = _elements.begin(), total = _elements.end(); it != total; ++it)
 	{
 		if (it != _elements.begin())
 		{
diff --git a/MongoDB/src/Binary.cpp b/MongoDB/src/Binary.cpp
index ea814d6969..604ac52c05 100644
--- a/MongoDB/src/Binary.cpp
+++ b/MongoDB/src/Binary.cpp
@@ -13,6 +13,10 @@
 
 
 #include "Poco/MongoDB/Binary.h"
+#include "Poco/Base64Encoder.h"
+#include "Poco/StreamCopier.h"
+#include "Poco/MemoryStream.h"
+#include <sstream>
 
 
 namespace Poco {
diff --git a/MongoDB/src/Database.cpp b/MongoDB/src/Database.cpp
index f00fc96813..ecd2ffd190 100644
--- a/MongoDB/src/Database.cpp
+++ b/MongoDB/src/Database.cpp
@@ -13,6 +13,7 @@
 
 
 #include "Poco/MongoDB/Database.h"
+#include "Poco/Base64Encoder.h"
 #include "Poco/MongoDB/Binary.h"
 #include "Poco/MD5Engine.h"
 #include "Poco/SHA1Engine.h"
diff --git a/MongoDB/src/Document.cpp b/MongoDB/src/Document.cpp
index f7c5c9c5dc..cfdf221ba3 100644
--- a/MongoDB/src/Document.cpp
+++ b/MongoDB/src/Document.cpp
@@ -47,7 +47,7 @@ Element::Ptr Document::get(const std::string& name) const
 {
 	Element::Ptr element;
 
-	ElementSet::const_iterator it = std::find_if(_elements.begin(), _elements.end(), ElementFindByName(name));
+	auto it = std::find_if(_elements.begin(), _elements.end(), ElementFindByName(name));
 	if (it != _elements.end())
 	{
 		return *it;
@@ -167,7 +167,7 @@ std::string Document::toString(int indent) const
 	if (indent > 0) oss << std::endl;
 
 
-	for (ElementSet::const_iterator it = _elements.begin(); it != _elements.end(); ++it)
+	for (auto it = _elements.begin(), total = _elements.end(); it != total; ++it)
 	{
 		if (it != _elements.begin())
 		{
diff --git a/MongoDB/testsuite/src/MongoDBTestOpMsg.cpp b/MongoDB/testsuite/src/MongoDBTestOpMsg.cpp
index 7d843e1214..113f66d548 100644
--- a/MongoDB/testsuite/src/MongoDBTestOpMsg.cpp
+++ b/MongoDB/testsuite/src/MongoDBTestOpMsg.cpp
@@ -60,7 +60,7 @@ void MongoDBTest::testOpCmdUUID()
 		Document::Ptr doc = response.documents()[0];
 		try
 		{
-			std::string name = doc->get<std::string>("name");
+			const auto& name = doc->get<std::string>("name");
 			assertEquals ("Barcelona", name );
 
 			Binary::Ptr uuidBinary = doc->get<Binary::Ptr>("uuid");
@@ -194,14 +194,14 @@ void MongoDBTest::testOpCmdFind()
 
 		try
 		{
-			std::string lastname = doc->get<std::string>("lastname");
+			const auto& lastname = doc->get<std::string>("lastname");
 			assertEquals ("Braem", lastname);
-			std::string firstname = doc->get<std::string>("firstname");
+			const auto& firstname = doc->get<std::string>("firstname");
 			assertEquals ("Franky", firstname);
-			Poco::Timestamp birthDateTimestamp = doc->get<Poco::Timestamp>("birthdate");
+			const auto& birthDateTimestamp = doc->get<Poco::Timestamp>("birthdate");
 			Poco::DateTime birthDate(birthDateTimestamp);
 			assertTrue (birthDate.year() == 1969 && birthDate.month() == 3 && birthDate.day() == 9);
-			Poco::Timestamp lastupdatedTimestamp = doc->get<Poco::Timestamp>("lastupdated");
+			const auto& lastupdatedTimestamp = doc->get<Poco::Timestamp>("lastupdated");
 			assertTrue (doc->isType<NullValue>("unknown"));
 			bool active = doc->get<bool>("active");
 			assertEquals (false, active);