diff --git a/client/browseZeroConf/browseAvahi.cpp b/client/browseZeroConf/browseAvahi.cpp
index 78084909..ac2068a1 100644
--- a/client/browseZeroConf/browseAvahi.cpp
+++ b/client/browseZeroConf/browseAvahi.cpp
@@ -27,10 +27,10 @@
 #include <time.h>
 
 
-static AvahiSimplePoll* simple_poll = NULL;
+static AvahiSimplePoll* simple_poll = nullptr;
 
 
-BrowseAvahi::BrowseAvahi() : client_(NULL), sb_(NULL)
+BrowseAvahi::BrowseAvahi() : client_(nullptr), sb_(nullptr)
 {
 }
 
@@ -45,15 +45,15 @@ void BrowseAvahi::cleanUp()
 {
     if (sb_)
         avahi_service_browser_free(sb_);
-    sb_ = NULL;
+    sb_ = nullptr;
 
     if (client_)
         avahi_client_free(client_);
-    client_ = NULL;
+    client_ = nullptr;
 
     if (simple_poll)
         avahi_simple_poll_free(simple_poll);
-    simple_poll = NULL;
+    simple_poll = nullptr;
 }
 
 
@@ -180,7 +180,7 @@ bool BrowseAvahi::browse(const std::string& serviceName, mDNSResult& result, int
 
         /* Create the service browser */
         if (!(sb_ =
-                  avahi_service_browser_new(client_, AVAHI_IF_UNSPEC, AVAHI_PROTO_INET, serviceName.c_str(), NULL, (AvahiLookupFlags)0, browse_callback, this)))
+                  avahi_service_browser_new(client_, AVAHI_IF_UNSPEC, AVAHI_PROTO_INET, serviceName.c_str(), nullptr, (AvahiLookupFlags)0, browse_callback, this)))
             throw SnapException("BrowseAvahi - Failed to create service browser: " + std::string(avahi_strerror(avahi_client_errno(client_))));
 
         result_.valid = false;
diff --git a/client/clientConnection.cpp b/client/clientConnection.cpp
index f66ee002..6bc7ef94 100644
--- a/client/clientConnection.cpp
+++ b/client/clientConnection.cpp
@@ -29,7 +29,7 @@ using namespace std;
 
 
 ClientConnection::ClientConnection(MessageReceiver* receiver, const std::string& host, size_t port)
-    : socket_(nullptr), active_(false), connected_(false), messageReceiver_(receiver), reqId_(1), host_(host), port_(port), readerThread_(NULL),
+    : socket_(nullptr), active_(false), connected_(false), messageReceiver_(receiver), reqId_(1), host_(host), port_(port), readerThread_(nullptr),
       sumTimeout_(chronos::msec(0))
 {
 }
@@ -116,7 +116,7 @@ void ClientConnection::stop()
     catch (...)
     {
     }
-    readerThread_ = NULL;
+    readerThread_ = nullptr;
     socket_.reset();
     LOG(DEBUG) << "readerThread terminated\n";
 }
@@ -142,7 +142,7 @@ bool ClientConnection::send(const msg::BaseMessage* message) const
 
 shared_ptr<msg::SerializedMessage> ClientConnection::sendRequest(const msg::BaseMessage* message, const chronos::msec& timeout)
 {
-    shared_ptr<msg::SerializedMessage> response(NULL);
+    shared_ptr<msg::SerializedMessage> response(nullptr);
     if (++reqId_ >= 10000)
         reqId_ = 1;
     message->id = reqId_;
@@ -209,7 +209,7 @@ void ClientConnection::getNextMessage()
         }
     }
 
-    if (messageReceiver_ != NULL)
+    if (messageReceiver_ != nullptr)
         messageReceiver_->onMessageReceived(this, baseMessage, &buffer[0]);
 }
 
@@ -226,7 +226,7 @@ void ClientConnection::reader()
     }
     catch (const std::exception& e)
     {
-        if (messageReceiver_ != NULL)
+        if (messageReceiver_ != nullptr)
             messageReceiver_->onException(this, make_shared<SnapException>(e.what()));
     }
     catch (...)
diff --git a/client/clientConnection.h b/client/clientConnection.h
index 7e26403f..4bd58a13 100644
--- a/client/clientConnection.h
+++ b/client/clientConnection.h
@@ -40,7 +40,7 @@ class ClientConnection;
 /// Used to synchronize server requests (wait for server response)
 struct PendingRequest
 {
-    PendingRequest(uint16_t reqId) : id(reqId), response(NULL){};
+    PendingRequest(uint16_t reqId) : id(reqId), response(nullptr){};
 
     uint16_t id;
     std::shared_ptr<msg::SerializedMessage> response;
@@ -87,7 +87,7 @@ public:
     {
         std::shared_ptr<msg::SerializedMessage> reply = sendRequest(message, timeout);
         if (!reply)
-            return NULL;
+            return nullptr;
         std::shared_ptr<T> msg(new T);
         msg->deserialize(reply->message, reply->buffer);
         return msg;
diff --git a/client/controller.cpp b/client/controller.cpp
index 4ce7e041..ddcb1fbd 100644
--- a/client/controller.cpp
+++ b/client/controller.cpp
@@ -57,7 +57,7 @@ void Controller::onMessageReceived(ClientConnection* connection, const msg::Base
     {
         if (stream_ && decoder_)
         {
-            msg::PcmChunk* pcmChunk = new msg::PcmChunk(sampleFormat_, 0);
+            auto* pcmChunk = new msg::PcmChunk(sampleFormat_, 0);
             pcmChunk->deserialize(baseMessage, buffer);
             //			LOG(DEBUG) << "chunk: " << pcmChunk->payloadSize << ", sampleFormat: " << sampleFormat_.rate << "\n";
             if (decoder_->decode(pcmChunk))
diff --git a/client/controller.h b/client/controller.h
index eb2c7415..5fc04dc7 100644
--- a/client/controller.h
+++ b/client/controller.h
@@ -54,11 +54,11 @@ public:
 
     /// Implementation of MessageReceiver.
     /// ClientConnection passes messages from the server through these callbacks
-    virtual void onMessageReceived(ClientConnection* connection, const msg::BaseMessage& baseMessage, char* buffer);
+    void onMessageReceived(ClientConnection* connection, const msg::BaseMessage& baseMessage, char* buffer) override;
 
     /// Implementation of MessageReceiver.
     /// Used for async exception reporting
-    virtual void onException(ClientConnection* connection, shared_exception_ptr exception);
+    void onException(ClientConnection* connection, shared_exception_ptr exception) override;
 
 private:
     void worker();
diff --git a/client/decoder/decoder.h b/client/decoder/decoder.h
index ca3c131c..742e1ee9 100644
--- a/client/decoder/decoder.h
+++ b/client/decoder/decoder.h
@@ -28,7 +28,7 @@ class Decoder
 {
 public:
     Decoder(){};
-    virtual ~Decoder(){};
+    virtual ~Decoder()= default;;
     virtual bool decode(msg::PcmChunk* chunk) = 0;
     virtual SampleFormat setHeader(msg::CodecHeader* chunk) = 0;
 
diff --git a/client/decoder/flacDecoder.cpp b/client/decoder/flacDecoder.cpp
index 8489f86f..3ee716e8 100644
--- a/client/decoder/flacDecoder.cpp
+++ b/client/decoder/flacDecoder.cpp
@@ -35,11 +35,11 @@ static void metadata_callback(const FLAC__StreamDecoder* decoder, const FLAC__St
 static void error_callback(const FLAC__StreamDecoder* decoder, FLAC__StreamDecoderErrorStatus status, void* client_data);
 
 
-static msg::CodecHeader* flacHeader = NULL;
-static msg::PcmChunk* flacChunk = NULL;
-static msg::PcmChunk* pcmChunk = NULL;
+static msg::CodecHeader* flacHeader = nullptr;
+static msg::PcmChunk* flacChunk = nullptr;
+static msg::PcmChunk* pcmChunk = nullptr;
 static SampleFormat sampleFormat;
-static FLAC__StreamDecoder* decoder = NULL;
+static FLAC__StreamDecoder* decoder = nullptr;
 
 
 
@@ -101,11 +101,11 @@ SampleFormat FlacDecoder::setHeader(msg::CodecHeader* chunk)
     flacHeader = chunk;
     FLAC__StreamDecoderInitStatus init_status;
 
-    if ((decoder = FLAC__stream_decoder_new()) == NULL)
+    if ((decoder = FLAC__stream_decoder_new()) == nullptr)
         throw SnapException("ERROR: allocating decoder");
 
     //	(void)FLAC__stream_decoder_set_md5_checking(decoder, true);
-    init_status = FLAC__stream_decoder_init_stream(decoder, read_callback, NULL, NULL, NULL, NULL, write_callback, metadata_callback, error_callback, this);
+    init_status = FLAC__stream_decoder_init_stream(decoder, read_callback, nullptr, nullptr, nullptr, nullptr, write_callback, metadata_callback, error_callback, this);
     if (init_status != FLAC__STREAM_DECODER_INIT_STATUS_OK)
         throw SnapException("ERROR: initializing decoder: " + string(FLAC__StreamDecoderInitStatusString[init_status]));
 
@@ -120,13 +120,13 @@ SampleFormat FlacDecoder::setHeader(msg::CodecHeader* chunk)
 
 FLAC__StreamDecoderReadStatus read_callback(const FLAC__StreamDecoder* decoder, FLAC__byte buffer[], size_t* bytes, void* client_data)
 {
-    if (flacHeader != NULL)
+    if (flacHeader != nullptr)
     {
         *bytes = flacHeader->payloadSize;
         memcpy(buffer, flacHeader->payload, *bytes);
-        flacHeader = NULL;
+        flacHeader = nullptr;
     }
-    else if (flacChunk != NULL)
+    else if (flacChunk != nullptr)
     {
         //		cerr << "read_callback: " << *bytes << ", avail: " << flacChunk->payloadSize << "\n";
         static_cast<FlacDecoder*>(client_data)->cacheInfo_.isCachedChunk_ = false;
@@ -150,7 +150,7 @@ FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder* decoder
 {
     (void)decoder;
 
-    if (pcmChunk != NULL)
+    if (pcmChunk != nullptr)
     {
         size_t bytes = frame->header.blocksize * sampleFormat.frameSize;
 
@@ -162,7 +162,7 @@ FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder* decoder
 
         for (size_t channel = 0; channel < sampleFormat.channels; ++channel)
         {
-            if (buffer[channel] == NULL)
+            if (buffer[channel] == nullptr)
             {
                 SLOG(ERROR) << "ERROR: buffer[" << channel << "] is NULL\n";
                 return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
diff --git a/client/decoder/flacDecoder.h b/client/decoder/flacDecoder.h
index 8d85f369..2b34e46f 100644
--- a/client/decoder/flacDecoder.h
+++ b/client/decoder/flacDecoder.h
@@ -50,9 +50,9 @@ class FlacDecoder : public Decoder
 {
 public:
     FlacDecoder();
-    virtual ~FlacDecoder();
-    virtual bool decode(msg::PcmChunk* chunk);
-    virtual SampleFormat setHeader(msg::CodecHeader* chunk);
+    ~FlacDecoder() override;
+    bool decode(msg::PcmChunk* chunk) override;
+    SampleFormat setHeader(msg::CodecHeader* chunk) override;
 
     CacheInfo cacheInfo_;
     std::unique_ptr<FLAC__StreamDecoderErrorStatus> lastError_;
diff --git a/client/decoder/oggDecoder.h b/client/decoder/oggDecoder.h
index bc9dddcf..6393142c 100644
--- a/client/decoder/oggDecoder.h
+++ b/client/decoder/oggDecoder.h
@@ -30,9 +30,9 @@ class OggDecoder : public Decoder
 {
 public:
     OggDecoder();
-    virtual ~OggDecoder();
-    virtual bool decode(msg::PcmChunk* chunk);
-    virtual SampleFormat setHeader(msg::CodecHeader* chunk);
+    ~OggDecoder() override;
+    bool decode(msg::PcmChunk* chunk) override;
+    SampleFormat setHeader(msg::CodecHeader* chunk) override;
 
 private:
     bool decodePayload(msg::PcmChunk* chunk);
diff --git a/client/decoder/pcmDecoder.h b/client/decoder/pcmDecoder.h
index b0b49cdd..f4c58464 100644
--- a/client/decoder/pcmDecoder.h
+++ b/client/decoder/pcmDecoder.h
@@ -25,8 +25,8 @@ class PcmDecoder : public Decoder
 {
 public:
     PcmDecoder();
-    virtual bool decode(msg::PcmChunk* chunk);
-    virtual SampleFormat setHeader(msg::CodecHeader* chunk);
+    bool decode(msg::PcmChunk* chunk) override;
+    SampleFormat setHeader(msg::CodecHeader* chunk) override;
 };
 
 
diff --git a/client/metadata.h b/client/metadata.h
index 14131967..43658081 100644
--- a/client/metadata.h
+++ b/client/metadata.h
@@ -93,7 +93,7 @@ class MetaStderrAdapter : public MetadataAdapter
 public:
     using MetadataAdapter::push;
 
-    int push()
+    int push() override
     {
         std::cerr << serialize() << "\n";
         return 0;
diff --git a/client/player/alsaPlayer.cpp b/client/player/alsaPlayer.cpp
index 8dd29b8a..a1c2c081 100644
--- a/client/player/alsaPlayer.cpp
+++ b/client/player/alsaPlayer.cpp
@@ -26,7 +26,7 @@
 
 using namespace std;
 
-AlsaPlayer::AlsaPlayer(const PcmDevice& pcmDevice, std::shared_ptr<Stream> stream) : Player(pcmDevice, stream), handle_(NULL), buff_(NULL)
+AlsaPlayer::AlsaPlayer(const PcmDevice& pcmDevice, std::shared_ptr<Stream> stream) : Player(pcmDevice, stream), handle_(nullptr), buff_(nullptr)
 {
 }
 
@@ -105,18 +105,18 @@ void AlsaPlayer::initAlsa()
     if ((pcm = snd_pcm_hw_params_set_channels(handle_, params, channels)) < 0)
         throw SnapException("Can't set channels number: " + string(snd_strerror(pcm)));
 
-    if ((pcm = snd_pcm_hw_params_set_rate_near(handle_, params, &rate, 0)) < 0)
+    if ((pcm = snd_pcm_hw_params_set_rate_near(handle_, params, &rate, nullptr)) < 0)
         throw SnapException("Can't set rate: " + string(snd_strerror(pcm)));
 
     unsigned int period_time;
-    snd_pcm_hw_params_get_period_time_max(params, &period_time, 0);
+    snd_pcm_hw_params_get_period_time_max(params, &period_time, nullptr);
     if (period_time > PERIOD_TIME)
         period_time = PERIOD_TIME;
 
     unsigned int buffer_time = 4 * period_time;
 
-    snd_pcm_hw_params_set_period_time_near(handle_, params, &period_time, 0);
-    snd_pcm_hw_params_set_buffer_time_near(handle_, params, &buffer_time, 0);
+    snd_pcm_hw_params_set_period_time_near(handle_, params, &period_time, nullptr);
+    snd_pcm_hw_params_set_buffer_time_near(handle_, params, &buffer_time, nullptr);
 
     //	long unsigned int periodsize = stream_->format.msRate() * 50;//2*rate/50;
     //	if ((pcm = snd_pcm_hw_params_set_buffer_size_near(pcm_handle, params, &periodsize)) < 0)
@@ -132,17 +132,17 @@ void AlsaPlayer::initAlsa()
     snd_pcm_hw_params_get_channels(params, &tmp);
     LOG(DEBUG) << "channels: " << tmp << "\n";
 
-    snd_pcm_hw_params_get_rate(params, &tmp, 0);
+    snd_pcm_hw_params_get_rate(params, &tmp, nullptr);
     LOG(DEBUG) << "rate: " << tmp << " bps\n";
 
     /* Allocate buffer to hold single period */
-    snd_pcm_hw_params_get_period_size(params, &frames_, 0);
+    snd_pcm_hw_params_get_period_size(params, &frames_, nullptr);
     LOG(INFO) << "frames: " << frames_ << "\n";
 
     buff_size = frames_ * format.frameSize; // channels * 2 /* 2 -> sample size */;
     buff_ = (char*)malloc(buff_size);
 
-    snd_pcm_hw_params_get_period_time(params, &tmp, NULL);
+    snd_pcm_hw_params_get_period_time(params, &tmp, nullptr);
     LOG(DEBUG) << "period time: " << tmp << "\n";
 
     snd_pcm_sw_params_t* swparams;
@@ -158,17 +158,17 @@ void AlsaPlayer::initAlsa()
 
 void AlsaPlayer::uninitAlsa()
 {
-    if (handle_ != NULL)
+    if (handle_ != nullptr)
     {
         snd_pcm_drain(handle_);
         snd_pcm_close(handle_);
-        handle_ = NULL;
+        handle_ = nullptr;
     }
 
-    if (buff_ != NULL)
+    if (buff_ != nullptr)
     {
         free(buff_);
-        buff_ = NULL;
+        buff_ = nullptr;
     }
 }
 
@@ -201,7 +201,7 @@ void AlsaPlayer::worker()
 
     while (active_)
     {
-        if (handle_ == NULL)
+        if (handle_ == nullptr)
         {
             try
             {
@@ -240,7 +240,7 @@ void AlsaPlayer::worker()
             while (active_ && !stream_->waitForChunk(100))
             {
                 LOG(DEBUG) << "Waiting for chunk\n";
-                if ((handle_ != NULL) && (chronos::getTickCount() - lastChunkTick > 5000))
+                if ((handle_ != nullptr) && (chronos::getTickCount() - lastChunkTick > 5000))
                 {
                     LOG(NOTICE) << "No chunk received for 5000ms. Closing ALSA.\n";
                     uninitAlsa();
@@ -253,7 +253,7 @@ void AlsaPlayer::worker()
 
 
 
-vector<PcmDevice> AlsaPlayer::pcm_list(void)
+vector<PcmDevice> AlsaPlayer::pcm_list()
 {
     void **hints, **n;
     char *name, *descr, *io;
@@ -264,15 +264,15 @@ vector<PcmDevice> AlsaPlayer::pcm_list(void)
         return result;
     n = hints;
     size_t idx(0);
-    while (*n != NULL)
+    while (*n != nullptr)
     {
         name = snd_device_name_get_hint(*n, "NAME");
         descr = snd_device_name_get_hint(*n, "DESC");
         io = snd_device_name_get_hint(*n, "IOID");
-        if (io != NULL && strcmp(io, "Output") != 0)
+        if (io != nullptr && strcmp(io, "Output") != 0)
             goto __end;
         pcmDevice.name = name;
-        if (descr == NULL)
+        if (descr == nullptr)
         {
             pcmDevice.description = "";
         }
@@ -284,11 +284,11 @@ vector<PcmDevice> AlsaPlayer::pcm_list(void)
         result.push_back(pcmDevice);
 
     __end:
-        if (name != NULL)
+        if (name != nullptr)
             free(name);
-        if (descr != NULL)
+        if (descr != nullptr)
             free(descr);
-        if (io != NULL)
+        if (io != nullptr)
             free(io);
         n++;
     }
diff --git a/client/player/alsaPlayer.h b/client/player/alsaPlayer.h
index 9138f706..6c4824c4 100644
--- a/client/player/alsaPlayer.h
+++ b/client/player/alsaPlayer.h
@@ -31,17 +31,17 @@ class AlsaPlayer : public Player
 {
 public:
     AlsaPlayer(const PcmDevice& pcmDevice, std::shared_ptr<Stream> stream);
-    virtual ~AlsaPlayer();
+    ~AlsaPlayer() override;
 
     /// Set audio volume in range [0..1]
-    virtual void start();
-    virtual void stop();
+    void start() override;
+    void stop() override;
 
     /// List the system's audio output devices
     static std::vector<PcmDevice> pcm_list(void);
 
 protected:
-    virtual void worker();
+    void worker() override;
 
 private:
     void initAlsa();
diff --git a/client/stream.cpp b/client/stream.cpp
index 5ef2c3bd..67b25df1 100644
--- a/client/stream.cpp
+++ b/client/stream.cpp
@@ -262,7 +262,7 @@ bool Stream::getPlayerChunk(void* outputBuffer, const cs::usec& outputBufferDacT
                     if (!chunks_.try_pop(chunk_, outputBufferDacTime))
                     {
                         LOG(INFO) << "no chunks available\n";
-                        chunk_ = NULL;
+                        chunk_ = nullptr;
                         sleep_ = cs::usec(0);
                         return false;
                     }
@@ -362,7 +362,7 @@ else if (miniBuffer_.full() && (cs::usec(abs(miniBuffer_.median())) > cs::msec(5
         updateBuffers(age.count());
 
         // print sync stats
-        time_t now = time(NULL);
+        time_t now = time(nullptr);
         if (now != lastUpdate_)
         {
             lastUpdate_ = now;
diff --git a/common/message/codecHeader.h b/common/message/codecHeader.h
index 8eb496c3..8829ce07 100644
--- a/common/message/codecHeader.h
+++ b/common/message/codecHeader.h
@@ -35,18 +35,18 @@ public:
         payload = (char*)malloc(size);
     }
 
-    virtual ~CodecHeader()
+    ~CodecHeader() override
     {
         free(payload);
     }
 
-    virtual void read(std::istream& stream)
+    void read(std::istream& stream) override
     {
         readVal(stream, codec);
         readVal(stream, &payload, payloadSize);
     }
 
-    virtual uint32_t getSize() const
+    uint32_t getSize() const override
     {
         return sizeof(uint32_t) + codec.size() + sizeof(uint32_t) + payloadSize;
     }
@@ -56,7 +56,7 @@ public:
     std::string codec;
 
 protected:
-    virtual void doserialize(std::ostream& stream) const
+    void doserialize(std::ostream& stream) const override
     {
         writeVal(stream, codec);
         writeVal(stream, payload, payloadSize);
diff --git a/common/message/hello.h b/common/message/hello.h
index f610ddfc..01bac5b7 100644
--- a/common/message/hello.h
+++ b/common/message/hello.h
@@ -48,9 +48,8 @@ public:
         msg["SnapStreamProtocolVersion"] = 2;
     }
 
-    virtual ~Hello()
-    {
-    }
+    ~Hello() override
+    = default;
 
     std::string getMacAddress() const
     {
diff --git a/common/message/jsonMessage.h b/common/message/jsonMessage.h
index 1f01cd2c..c730d7d4 100644
--- a/common/message/jsonMessage.h
+++ b/common/message/jsonMessage.h
@@ -36,18 +36,17 @@ public:
     {
     }
 
-    virtual ~JsonMessage()
-    {
-    }
+    ~JsonMessage() override
+    = default;
 
-    virtual void read(std::istream& stream)
+    void read(std::istream& stream) override
     {
         std::string s;
         readVal(stream, s);
         msg = json::parse(s);
     }
 
-    virtual uint32_t getSize() const
+    uint32_t getSize() const override
     {
         return sizeof(uint32_t) + msg.dump().size();
     }
@@ -56,7 +55,7 @@ public:
 
 
 protected:
-    virtual void doserialize(std::ostream& stream) const
+    void doserialize(std::ostream& stream) const override
     {
         writeVal(stream, msg.dump());
     }
diff --git a/common/message/message.h b/common/message/message.h
index 8743279f..dffd9b25 100644
--- a/common/message/message.h
+++ b/common/message/message.h
@@ -127,8 +127,7 @@ struct BaseMessage
     }
 
     virtual ~BaseMessage()
-    {
-    }
+    = default;
 
     virtual void read(std::istream& stream)
     {
diff --git a/common/message/pcmChunk.h b/common/message/pcmChunk.h
index 68e56a68..a4e6579f 100644
--- a/common/message/pcmChunk.h
+++ b/common/message/pcmChunk.h
@@ -48,9 +48,8 @@ public:
     {
     }
 
-    virtual ~PcmChunk()
-    {
-    }
+    ~PcmChunk() override
+    = default;
 
     int readFrames(void* outputBuffer, size_t frameCount)
     {
@@ -60,7 +59,7 @@ public:
             result = (payloadSize / format.frameSize) - idx_;
 
         // logd << ", from: " << format.frameSize*idx << ", to: " << format.frameSize*idx + format.frameSize*result;
-        if (outputBuffer != NULL)
+        if (outputBuffer != nullptr)
             memcpy((char*)outputBuffer, (char*)(payload) + format.frameSize * idx_, format.frameSize * result);
 
         idx_ += result;
@@ -82,7 +81,7 @@ public:
     }
 
 
-    virtual chronos::time_point_clk start() const
+    chronos::time_point_clk start() const override
     {
         return chronos::time_point_clk(chronos::sec(timestamp.sec) + chronos::usec(timestamp.usec) +
                                        chronos::usec((chronos::usec::rep)(1000000. * ((double)idx_ / (double)format.rate))));
diff --git a/common/message/serverSettings.h b/common/message/serverSettings.h
index a23a391c..a926da5a 100644
--- a/common/message/serverSettings.h
+++ b/common/message/serverSettings.h
@@ -36,9 +36,8 @@ public:
         setMuted(false);
     }
 
-    virtual ~ServerSettings()
-    {
-    }
+    ~ServerSettings() override
+    = default;
 
     int32_t getBufferMs()
     {
diff --git a/common/message/streamTags.h b/common/message/streamTags.h
index c3eee316..62539d38 100644
--- a/common/message/streamTags.h
+++ b/common/message/streamTags.h
@@ -65,9 +65,8 @@ public:
     {
     }
 
-    virtual ~StreamTags()
-    {
-    }
+    ~StreamTags() override
+    = default;
 };
 }
 
diff --git a/common/message/time.h b/common/message/time.h
index 43391aeb..59d79483 100644
--- a/common/message/time.h
+++ b/common/message/time.h
@@ -31,17 +31,16 @@ public:
     {
     }
 
-    virtual ~Time()
-    {
-    }
+    ~Time() override
+    = default;
 
-    virtual void read(std::istream& stream)
+    void read(std::istream& stream) override
     {
         readVal(stream, latency.sec);
         readVal(stream, latency.usec);
     }
 
-    virtual uint32_t getSize() const
+    uint32_t getSize() const override
     {
         return sizeof(tv);
     }
@@ -49,7 +48,7 @@ public:
     tv latency;
 
 protected:
-    virtual void doserialize(std::ostream& stream) const
+    void doserialize(std::ostream& stream) const override
     {
         writeVal(stream, latency.sec);
         writeVal(stream, latency.usec);
diff --git a/common/message/wireChunk.h b/common/message/wireChunk.h
index f8c65e71..3ee2d8e8 100644
--- a/common/message/wireChunk.h
+++ b/common/message/wireChunk.h
@@ -50,19 +50,19 @@ public:
         memcpy(payload, wireChunk.payload, payloadSize);
     }
 
-    virtual ~WireChunk()
+    ~WireChunk() override
     {
         free(payload);
     }
 
-    virtual void read(std::istream& stream)
+    void read(std::istream& stream) override
     {
         readVal(stream, timestamp.sec);
         readVal(stream, timestamp.usec);
         readVal(stream, &payload, payloadSize);
     }
 
-    virtual uint32_t getSize() const
+    uint32_t getSize() const override
     {
         return sizeof(tv) + sizeof(int32_t) + payloadSize;
     }
@@ -77,7 +77,7 @@ public:
     char* payload;
 
 protected:
-    virtual void doserialize(std::ostream& stream) const
+    void doserialize(std::ostream& stream) const override
     {
         writeVal(stream, timestamp.sec);
         writeVal(stream, timestamp.usec);
diff --git a/common/sampleFormat.cpp b/common/sampleFormat.cpp
index 2de06cd7..5351bd36 100644
--- a/common/sampleFormat.cpp
+++ b/common/sampleFormat.cpp
@@ -31,8 +31,7 @@ using namespace std;
 
 
 SampleFormat::SampleFormat()
-{
-}
+= default;
 
 
 SampleFormat::SampleFormat(const std::string& format)
diff --git a/common/snapException.h b/common/snapException.h
index 2ca86487..4439c46e 100644
--- a/common/snapException.h
+++ b/common/snapException.h
@@ -43,12 +43,12 @@ public:
     {
     }
 
-    virtual ~SnapException() throw()
+    ~SnapException() throw() override
     {
         delete[] text_;
     }
 
-    virtual const char* what() const noexcept
+    const char* what() const noexcept override
     {
         return text_;
     }
@@ -72,9 +72,8 @@ public:
     }
 
 
-    virtual ~AsyncSnapException() throw()
-    {
-    }
+    ~AsyncSnapException() throw() override
+    = default;
 };
 
 
diff --git a/common/timeDefs.h b/common/timeDefs.h
index 9e6f2221..de97c889 100644
--- a/common/timeDefs.h
+++ b/common/timeDefs.h
@@ -47,7 +47,7 @@ inline static void timeofday(struct timeval* tv)
 
 inline static void systemtimeofday(struct timeval* tv)
 {
-    gettimeofday(tv, NULL);
+    gettimeofday(tv, nullptr);
     // timeofday<std::chrono::system_clock>(tv);
 }
 
diff --git a/common/utils.h b/common/utils.h
index 8c6cc256..d56930d9 100644
--- a/common/utils.h
+++ b/common/utils.h
@@ -69,7 +69,7 @@ static std::string execGetOutput(const std::string& cmd)
     std::string result = "";
     while (!feof(pipe.get()))
     {
-        if (fgets(buffer, 1024, pipe.get()) != NULL)
+        if (fgets(buffer, 1024, pipe.get()) != nullptr)
             result += buffer;
     }
     return strutils::trim(result);
@@ -182,7 +182,7 @@ static std::string generateUUID()
     static bool initialized(false);
     if (!initialized)
     {
-        std::srand(std::time(0));
+        std::srand(std::time(nullptr));
         initialized = true;
     }
     std::stringstream ss;
diff --git a/common/utils/file_utils.h b/common/utils/file_utils.h
index ee7a1e60..ec9f3f64 100644
--- a/common/utils/file_utils.h
+++ b/common/utils/file_utils.h
@@ -54,7 +54,7 @@ static void do_chown(const std::string& file_path, const std::string& user_name,
     if (!user_name.empty())
     {
         struct passwd* pwd = getpwnam(user_name.c_str());
-        if (pwd == NULL)
+        if (pwd == nullptr)
             throw std::runtime_error("Failed to get uid");
         uid = pwd->pw_uid;
     }
@@ -62,7 +62,7 @@ static void do_chown(const std::string& file_path, const std::string& user_name,
     if (!group_name.empty())
     {
         struct group* grp = getgrnam(group_name.c_str());
-        if (grp == NULL)
+        if (grp == nullptr)
             throw std::runtime_error("Failed to get gid");
         gid = grp->gr_gid;
     }
diff --git a/server/config.cpp b/server/config.cpp
index 46fec0a0..2b2bbbed 100644
--- a/server/config.cpp
+++ b/server/config.cpp
@@ -46,7 +46,7 @@ void Config::init(const std::string& root_directory, const std::string& user, co
     string dir;
     if (!root_directory.empty())
         dir = root_directory;
-    else if (getenv("HOME") == NULL)
+    else if (getenv("HOME") == nullptr)
         dir = "/var/lib/snapserver/";
     else
         dir = getenv("HOME");
@@ -97,10 +97,10 @@ void Config::init(const std::string& root_directory, const std::string& user, co
             if (j.count("ConfigVersion"))
             {
                 json jGroups = j["Groups"];
-                for (auto it = jGroups.begin(); it != jGroups.end(); ++it)
+                for (auto & jGroup : jGroups)
                 {
                     GroupPtr group = make_shared<Group>();
-                    group->fromJson(*it);
+                    group->fromJson(jGroup);
                     //					if (client->id.empty() || getClientInfo(client->id))
                     //						continue;
                     groups.push_back(group);
diff --git a/server/config.h b/server/config.h
index 81db9cb2..e5be9583 100644
--- a/server/config.h
+++ b/server/config.h
@@ -161,8 +161,7 @@ struct Snapcast
     }
 
     virtual ~Snapcast()
-    {
-    }
+    = default;
 
     virtual void fromJson(const json& j)
     {
@@ -200,13 +199,13 @@ struct Snapserver : public Snapcast
     {
     }
 
-    virtual void fromJson(const json& j)
+    void fromJson(const json& j) override
     {
         Snapcast::fromJson(j);
         controlProtocolVersion = jGet<int>(j, "controlProtocolVersion", 1);
     }
 
-    virtual json toJson()
+    json toJson() override
     {
         json j = Snapcast::toJson();
         j["controlProtocolVersion"] = controlProtocolVersion;
diff --git a/server/controlServer.cpp b/server/controlServer.cpp
index 8f437ea4..24acb5cb 100644
--- a/server/controlServer.cpp
+++ b/server/controlServer.cpp
@@ -94,7 +94,7 @@ void ControlServer::onMessageReceived(ControlSession* connection, const std::str
     }
     else
     {
-        if (controlMessageReceiver_ != NULL)
+        if (controlMessageReceiver_ != nullptr)
             controlMessageReceiver_->onMessageReceived(connection, message);
     }
 }
diff --git a/server/controlServer.h b/server/controlServer.h
index 13c7eecc..6459b4b2 100644
--- a/server/controlServer.h
+++ b/server/controlServer.h
@@ -46,17 +46,17 @@ typedef std::shared_ptr<tcp::socket> socket_ptr;
 class ControlServer : public ControlMessageReceiver
 {
 public:
-    ControlServer(asio::io_service* io_service, size_t port, ControlMessageReceiver* controlMessageReceiver = NULL);
+    ControlServer(asio::io_service* io_service, size_t port, ControlMessageReceiver* controlMessageReceiver = nullptr);
     virtual ~ControlServer();
 
     void start();
     void stop();
 
     /// Send a message to all connceted clients
-    void send(const std::string& message, const ControlSession* excludeSession = NULL);
+    void send(const std::string& message, const ControlSession* excludeSession = nullptr);
 
     /// Clients call this when they receive a message. Implementation of MessageReceiver::onMessageReceived
-    virtual void onMessageReceived(ControlSession* connection, const std::string& message);
+    void onMessageReceived(ControlSession* connection, const std::string& message) override;
 
 private:
     void startAccept();
diff --git a/server/controlSession.cpp b/server/controlSession.cpp
index 53436bb4..21e549f2 100644
--- a/server/controlSession.cpp
+++ b/server/controlSession.cpp
@@ -82,7 +82,7 @@ void ControlSession::stop()
     catch (...)
     {
     }
-    socket_ = NULL;
+    socket_ = nullptr;
     LOG(DEBUG) << "ControlSession ControlSession stopped\n";
 }
 
@@ -137,7 +137,7 @@ void ControlSession::reader()
                 if ((len >= 2) && line[len - 2] == '\r')
                     --len;
                 line.resize(len);
-                if ((messageReceiver_ != NULL) && !line.empty())
+                if ((messageReceiver_ != nullptr) && !line.empty())
                     messageReceiver_->onMessageReceived(this, line);
             }
             message.str("");
diff --git a/server/encoder/encoder.h b/server/encoder/encoder.h
index a58ed8ef..a70dad00 100644
--- a/server/encoder/encoder.h
+++ b/server/encoder/encoder.h
@@ -50,13 +50,12 @@ class Encoder
 {
 public:
     /// ctor. Codec options (E.g. compression level) are passed as string and are codec dependend
-    Encoder(const std::string& codecOptions = "") : headerChunk_(NULL), codecOptions_(codecOptions)
+    Encoder(const std::string& codecOptions = "") : headerChunk_(nullptr), codecOptions_(codecOptions)
     {
     }
 
     virtual ~Encoder()
-    {
-    }
+    = default;
 
     /// The listener will receive the encoded stream
     virtual void init(EncoderListener* listener, const SampleFormat& format)
diff --git a/server/encoder/flacEncoder.cpp b/server/encoder/flacEncoder.cpp
index 59d934cd..8a0b7c0e 100644
--- a/server/encoder/flacEncoder.cpp
+++ b/server/encoder/flacEncoder.cpp
@@ -26,7 +26,7 @@
 using namespace std;
 
 
-FlacEncoder::FlacEncoder(const std::string& codecOptions) : Encoder(codecOptions), encoder_(NULL), pcmBufferSize_(0), encodedSamples_(0)
+FlacEncoder::FlacEncoder(const std::string& codecOptions) : Encoder(codecOptions), encoder_(nullptr), pcmBufferSize_(0), encodedSamples_(0)
 {
     flacChunk_ = new msg::PcmChunk();
     headerChunk_.reset(new msg::CodecHeader("flac"));
@@ -36,7 +36,7 @@ FlacEncoder::FlacEncoder(const std::string& codecOptions) : Encoder(codecOptions
 
 FlacEncoder::~FlacEncoder()
 {
-    if (encoder_ != NULL)
+    if (encoder_ != nullptr)
     {
         FLAC__stream_encoder_finish(encoder_);
         FLAC__metadata_object_delete(metadata_[0]);
@@ -163,7 +163,7 @@ void FlacEncoder::initEncoder()
     FLAC__StreamMetadata_VorbisComment_Entry entry;
 
     // allocate the encoder
-    if ((encoder_ = FLAC__stream_encoder_new()) == NULL)
+    if ((encoder_ = FLAC__stream_encoder_new()) == nullptr)
         throw SnapException("error allocating encoder");
 
     ok &= FLAC__stream_encoder_set_verify(encoder_, true);
@@ -181,8 +181,8 @@ void FlacEncoder::initEncoder()
         throw SnapException("error setting up encoder");
 
     // now add some metadata; we'll add some tags and a padding block
-    if ((metadata_[0] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT)) == NULL ||
-        (metadata_[1] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)) == NULL ||
+    if ((metadata_[0] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT)) == nullptr ||
+        (metadata_[1] = FLAC__metadata_object_new(FLAC__METADATA_TYPE_PADDING)) == nullptr ||
         // there are many tag (vorbiscomment) functions but these are convenient for this particular use:
         !FLAC__metadata_object_vorbiscomment_entry_from_name_value_pair(&entry, "TITLE", "SnapStream") ||
         !FLAC__metadata_object_vorbiscomment_append_comment(metadata_[0], entry, false) ||
@@ -196,7 +196,7 @@ void FlacEncoder::initEncoder()
         throw SnapException("error setting meta data");
 
     // initialize encoder
-    init_status = FLAC__stream_encoder_init_stream(encoder_, ::write_callback, NULL, NULL, NULL, this);
+    init_status = FLAC__stream_encoder_init_stream(encoder_, ::write_callback, nullptr, nullptr, nullptr, this);
     if (init_status != FLAC__STREAM_ENCODER_INIT_STATUS_OK)
         throw SnapException("ERROR: initializing encoder: " + string(FLAC__StreamEncoderInitStatusString[init_status]));
 }
diff --git a/server/encoder/flacEncoder.h b/server/encoder/flacEncoder.h
index eed3ac4a..6e5de9b0 100644
--- a/server/encoder/flacEncoder.h
+++ b/server/encoder/flacEncoder.h
@@ -31,17 +31,17 @@ class FlacEncoder : public Encoder
 {
 public:
     FlacEncoder(const std::string& codecOptions = "");
-    ~FlacEncoder();
-    virtual void encode(const msg::PcmChunk* chunk);
-    virtual std::string getAvailableOptions() const;
-    virtual std::string getDefaultOptions() const;
-    virtual std::string name() const;
+    ~FlacEncoder() override;
+    void encode(const msg::PcmChunk* chunk) override;
+    std::string getAvailableOptions() const override;
+    std::string getDefaultOptions() const override;
+    std::string name() const override;
 
     FLAC__StreamEncoderWriteStatus write_callback(const FLAC__StreamEncoder* encoder, const FLAC__byte buffer[], size_t bytes, unsigned samples,
                                                   unsigned current_frame);
 
 protected:
-    virtual void initEncoder();
+    void initEncoder() override;
 
     FLAC__StreamEncoder* encoder_;
     FLAC__StreamMetadata* metadata_[2];
diff --git a/server/encoder/oggEncoder.cpp b/server/encoder/oggEncoder.cpp
index e3c745a0..f942d48b 100644
--- a/server/encoder/oggEncoder.cpp
+++ b/server/encoder/oggEncoder.cpp
@@ -86,7 +86,7 @@ void OggEncoder::encode(const msg::PcmChunk* chunk)
     /* tell the library how much we actually submitted */
     vorbis_analysis_wrote(&vd_, frames);
 
-    msg::PcmChunk* oggChunk = new msg::PcmChunk(chunk->format, 0);
+    auto* oggChunk = new msg::PcmChunk(chunk->format, 0);
 
     /* vorbis does some data preanalysis, then divvies up blocks for
     more involved (potentially parallel) processing.  Get a single
@@ -95,7 +95,7 @@ void OggEncoder::encode(const msg::PcmChunk* chunk)
     while (vorbis_analysis_blockout(&vd_, &vb_) == 1)
     {
         /* analysis, assume we want to use bitrate management */
-        vorbis_analysis(&vb_, NULL);
+        vorbis_analysis(&vb_, nullptr);
         vorbis_bitrate_addblock(&vb_);
 
         while (vorbis_bitrate_flushpacket(&vd_, &op_))
@@ -219,7 +219,7 @@ void OggEncoder::initEncoder()
     /* set up our packet->stream encoder */
     /* pick a random serial number; that way we can more likely build
      chained streams just by concatenation */
-    srand(time(NULL));
+    srand(time(nullptr));
     ogg_stream_init(&os_, rand());
 
     /* Vorbis streams begin with three headers; the initial header (with
diff --git a/server/encoder/oggEncoder.h b/server/encoder/oggEncoder.h
index be5df60e..583a45cf 100644
--- a/server/encoder/oggEncoder.h
+++ b/server/encoder/oggEncoder.h
@@ -26,13 +26,13 @@ class OggEncoder : public Encoder
 {
 public:
     OggEncoder(const std::string& codecOptions = "");
-    virtual void encode(const msg::PcmChunk* chunk);
-    virtual std::string getAvailableOptions() const;
-    virtual std::string getDefaultOptions() const;
-    virtual std::string name() const;
+    void encode(const msg::PcmChunk* chunk) override;
+    std::string getAvailableOptions() const override;
+    std::string getDefaultOptions() const override;
+    std::string name() const override;
 
 protected:
-    virtual void initEncoder();
+    void initEncoder() override;
 
 private:
     ogg_stream_state os_; /// take physical pages, weld into a logical stream of packets
diff --git a/server/encoder/pcmEncoder.cpp b/server/encoder/pcmEncoder.cpp
index 8e25e344..08a574fb 100644
--- a/server/encoder/pcmEncoder.cpp
+++ b/server/encoder/pcmEncoder.cpp
@@ -35,7 +35,7 @@ PcmEncoder::PcmEncoder(const std::string& codecOptions) : Encoder(codecOptions)
 
 void PcmEncoder::encode(const msg::PcmChunk* chunk)
 {
-    msg::PcmChunk* pcmChunk = new msg::PcmChunk(*chunk);
+    auto* pcmChunk = new msg::PcmChunk(*chunk);
     listener_->onChunkEncoded(this, pcmChunk, pcmChunk->duration<chronos::msec>().count());
 }
 
diff --git a/server/encoder/pcmEncoder.h b/server/encoder/pcmEncoder.h
index 0fbd3d86..208abbac 100644
--- a/server/encoder/pcmEncoder.h
+++ b/server/encoder/pcmEncoder.h
@@ -25,11 +25,11 @@ class PcmEncoder : public Encoder
 {
 public:
     PcmEncoder(const std::string& codecOptions = "");
-    virtual void encode(const msg::PcmChunk* chunk);
-    virtual std::string name() const;
+    void encode(const msg::PcmChunk* chunk) override;
+    std::string name() const override;
 
 protected:
-    virtual void initEncoder();
+    void initEncoder() override;
 
     template <typename T>
     void assign(void* pointer, T val)
diff --git a/server/publishZeroConf/publishAvahi.cpp b/server/publishZeroConf/publishAvahi.cpp
index 7031d3fe..c7282de5 100644
--- a/server/publishZeroConf/publishAvahi.cpp
+++ b/server/publishZeroConf/publishAvahi.cpp
@@ -27,10 +27,10 @@ static AvahiEntryGroup* group;
 static AvahiSimplePoll* simple_poll;
 static char* name;
 
-PublishAvahi::PublishAvahi(const std::string& serviceName) : PublishmDNS(serviceName), client_(NULL), active_(false)
+PublishAvahi::PublishAvahi(const std::string& serviceName) : PublishmDNS(serviceName), client_(nullptr), active_(false)
 {
-    group = NULL;
-    simple_poll = NULL;
+    group = nullptr;
+    simple_poll = nullptr;
     name = avahi_strdup(serviceName_.c_str());
 }
 
@@ -85,7 +85,7 @@ PublishAvahi::~PublishAvahi()
 
 void PublishAvahi::entry_group_callback(AvahiEntryGroup* g, AvahiEntryGroupState state, AVAHI_GCC_UNUSED void* userdata)
 {
-    assert(g == group || group == NULL);
+    assert(g == group || group == nullptr);
     group = g;
 
     /// Called whenever the entry group state changes
@@ -149,7 +149,7 @@ void PublishAvahi::create_services(AvahiClient* c)
         /// We will now add two services and one subtype to the entry group
         for (const auto& service : services_)
         {
-            if ((ret = avahi_entry_group_add_service(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, AvahiPublishFlags(0), name, service.name_.c_str(), NULL, NULL,
+            if ((ret = avahi_entry_group_add_service(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, AvahiPublishFlags(0), name, service.name_.c_str(), nullptr, nullptr,
                                                      service.port_, NULL)) < 0)
             {
                 if (ret == AVAHI_ERR_COLLISION)
diff --git a/server/publishZeroConf/publishAvahi.h b/server/publishZeroConf/publishAvahi.h
index 79e02613..cc9135d4 100644
--- a/server/publishZeroConf/publishAvahi.h
+++ b/server/publishZeroConf/publishAvahi.h
@@ -41,8 +41,8 @@ class PublishAvahi : public PublishmDNS
 {
 public:
     PublishAvahi(const std::string& serviceName);
-    virtual ~PublishAvahi();
-    virtual void publish(const std::vector<mDNSService>& services);
+    ~PublishAvahi() override;
+    void publish(const std::vector<mDNSService>& services) override;
 
 private:
     static void entry_group_callback(AvahiEntryGroup* g, AvahiEntryGroupState state, AVAHI_GCC_UNUSED void* userdata);
diff --git a/server/publishZeroConf/publishmDNS.h b/server/publishZeroConf/publishmDNS.h
index affd26c4..237deeda 100644
--- a/server/publishZeroConf/publishmDNS.h
+++ b/server/publishZeroConf/publishmDNS.h
@@ -24,8 +24,7 @@ public:
     }
 
     virtual ~PublishmDNS()
-    {
-    }
+    = default;
 
     virtual void publish(const std::vector<mDNSService>& services) = 0;
 
diff --git a/server/streamServer.cpp b/server/streamServer.cpp
index 79d0a327..f3da1d15 100644
--- a/server/streamServer.cpp
+++ b/server/streamServer.cpp
@@ -36,8 +36,7 @@ StreamServer::StreamServer(asio::io_service* io_service, const StreamServerSetti
 
 
 StreamServer::~StreamServer()
-{
-}
+= default;
 
 
 void StreamServer::onMetaChanged(const PcmStream* pcmStream)
@@ -57,7 +56,7 @@ void StreamServer::onMetaChanged(const PcmStream* pcmStream)
 
     LOG(INFO) << "onMetaChanged (" << pcmStream->getName() << ")\n";
     json notification = jsonrpcpp::Notification("Stream.OnMetadata", jsonrpcpp::Parameter("id", pcmStream->getId(), "meta", meta->msg)).to_json();
-    controlServer_->send(notification.dump(), NULL);
+    controlServer_->send(notification.dump(), nullptr);
     ////cout << "Notification: " << notification.dump() << "\n";
 }
 
@@ -69,7 +68,7 @@ void StreamServer::onStateChanged(const PcmStream* pcmStream, const ReaderState&
     LOG(INFO) << "onStateChanged (" << pcmStream->getName() << "): " << state << "\n";
     //	LOG(INFO) << pcmStream->toJson().dump(4);
     json notification = jsonrpcpp::Notification("Stream.OnUpdate", jsonrpcpp::Parameter("id", pcmStream->getId(), "stream", pcmStream->toJson())).to_json();
-    controlServer_->send(notification.dump(), NULL);
+    controlServer_->send(notification.dump(), nullptr);
     ////cout << "Notification: " << notification.dump() << "\n";
 }
 
diff --git a/server/streamServer.h b/server/streamServer.h
index 3229ede0..5c286036 100644
--- a/server/streamServer.h
+++ b/server/streamServer.h
@@ -79,17 +79,17 @@ public:
     //	void send(const msg::BaseMessage* message);
 
     /// Clients call this when they receive a message. Implementation of MessageReceiver::onMessageReceived
-    virtual void onMessageReceived(StreamSession* connection, const msg::BaseMessage& baseMessage, char* buffer);
-    virtual void onDisconnect(StreamSession* connection);
+    void onMessageReceived(StreamSession* connection, const msg::BaseMessage& baseMessage, char* buffer) override;
+    void onDisconnect(StreamSession* connection) override;
 
     /// Implementation of ControllMessageReceiver::onMessageReceived, called by ControlServer::onMessageReceived
-    virtual void onMessageReceived(ControlSession* connection, const std::string& message);
+    void onMessageReceived(ControlSession* connection, const std::string& message) override;
 
     /// Implementation of PcmListener
-    virtual void onMetaChanged(const PcmStream* pcmStream);
-    virtual void onStateChanged(const PcmStream* pcmStream, const ReaderState& state);
-    virtual void onChunkRead(const PcmStream* pcmStream, msg::PcmChunk* chunk, double duration);
-    virtual void onResync(const PcmStream* pcmStream, double ms);
+    void onMetaChanged(const PcmStream* pcmStream) override;
+    void onStateChanged(const PcmStream* pcmStream, const ReaderState& state) override;
+    void onChunkRead(const PcmStream* pcmStream, msg::PcmChunk* chunk, double duration) override;
+    void onResync(const PcmStream* pcmStream, double ms) override;
 
 private:
     void startAccept();
diff --git a/server/streamSession.cpp b/server/streamSession.cpp
index 63e22d60..632760d7 100644
--- a/server/streamSession.cpp
+++ b/server/streamSession.cpp
@@ -200,7 +200,7 @@ void StreamSession::getNextMessage()
     tv t;
     baseMessage.received = t;
 
-    if (active_ && (messageReceiver_ != NULL))
+    if (active_ && (messageReceiver_ != nullptr))
         messageReceiver_->onMessageReceived(this, baseMessage, &buffer[0]);
 }
 
@@ -219,7 +219,7 @@ void StreamSession::reader()
         SLOG(ERROR) << "Exception in StreamSession::reader(): " << e.what() << endl;
     }
 
-    if (active_ && (messageReceiver_ != NULL))
+    if (active_ && (messageReceiver_ != nullptr))
         messageReceiver_->onDisconnect(this);
 }
 
@@ -238,7 +238,7 @@ void StreamSession::writer()
                 if (bufferMs_ > 0)
                 {
                     const msg::WireChunk* wireChunk = dynamic_cast<const msg::WireChunk*>(message.get());
-                    if (wireChunk != NULL)
+                    if (wireChunk != nullptr)
                     {
                         chronos::time_point_clk now = chronos::clk::now();
                         size_t age = 0;
@@ -258,6 +258,6 @@ void StreamSession::writer()
         SLOG(ERROR) << "Exception in StreamSession::writer(): " << e.what() << endl;
     }
 
-    if (active_ && (messageReceiver_ != NULL))
+    if (active_ && (messageReceiver_ != nullptr))
         messageReceiver_->onDisconnect(this);
 }
diff --git a/server/streamreader/airplayStream.cpp b/server/streamreader/airplayStream.cpp
index 38a7de8f..5e17678b 100644
--- a/server/streamreader/airplayStream.cpp
+++ b/server/streamreader/airplayStream.cpp
@@ -28,7 +28,7 @@ using namespace std;
 static string hex2str(string input)
 {
     typedef unsigned char byte;
-    unsigned long x = strtoul(input.c_str(), 0, 16);
+    unsigned long x = strtoul(input.c_str(), nullptr, 16);
     byte a[] = {byte(x >> 24), byte(x >> 16), byte(x >> 8), byte(x), 0};
     return string((char*)a);
 }
diff --git a/server/streamreader/airplayStream.h b/server/streamreader/airplayStream.h
index d8a6ae68..4c69f13d 100644
--- a/server/streamreader/airplayStream.h
+++ b/server/streamreader/airplayStream.h
@@ -57,7 +57,7 @@ class AirplayStream : public ProcessStream
 public:
     /// ctor. Encoded PCM data is passed to the PipeListener
     AirplayStream(PcmListener* pcmListener, const StreamUri& uri);
-    virtual ~AirplayStream();
+    ~AirplayStream() override;
 
 protected:
 #ifdef HAS_EXPAT
@@ -74,8 +74,8 @@ protected:
     void push();
 #endif
 
-    virtual void onStderrMsg(const char* buffer, size_t n);
-    virtual void initExeAndPath(const std::string& filename);
+    void onStderrMsg(const char* buffer, size_t n) override;
+    void initExeAndPath(const std::string& filename) override;
     size_t port_;
     std::string pipePath_;
     std::string params_wo_port_;
diff --git a/server/streamreader/fileStream.h b/server/streamreader/fileStream.h
index 333a50b5..2c68ea46 100644
--- a/server/streamreader/fileStream.h
+++ b/server/streamreader/fileStream.h
@@ -34,10 +34,10 @@ class FileStream : public PcmStream
 public:
     /// ctor. Encoded PCM data is passed to the PipeListener
     FileStream(PcmListener* pcmListener, const StreamUri& uri);
-    virtual ~FileStream();
+    ~FileStream() override;
 
 protected:
-    virtual void worker();
+    void worker() override;
     std::ifstream ifs;
 };
 
diff --git a/server/streamreader/pcmStream.h b/server/streamreader/pcmStream.h
index 9311f177..a4ced5a8 100644
--- a/server/streamreader/pcmStream.h
+++ b/server/streamreader/pcmStream.h
@@ -75,7 +75,7 @@ public:
     virtual void stop();
 
     /// Implementation of EncoderListener::onChunkEncoded
-    virtual void onChunkEncoded(const Encoder* encoder, msg::PcmChunk* chunk, double duration);
+    void onChunkEncoded(const Encoder* encoder, msg::PcmChunk* chunk, double duration) override;
     virtual std::shared_ptr<msg::CodecHeader> getHeader();
 
     virtual const StreamUri& getUri() const;
diff --git a/server/streamreader/pipeStream.h b/server/streamreader/pipeStream.h
index dafbe82f..18937b34 100644
--- a/server/streamreader/pipeStream.h
+++ b/server/streamreader/pipeStream.h
@@ -34,10 +34,10 @@ class PipeStream : public PcmStream
 public:
     /// ctor. Encoded PCM data is passed to the PipeListener
     PipeStream(PcmListener* pcmListener, const StreamUri& uri);
-    virtual ~PipeStream();
+    ~PipeStream() override;
 
 protected:
-    virtual void worker();
+    void worker() override;
     int fd_;
 };
 
diff --git a/server/streamreader/processStream.h b/server/streamreader/processStream.h
index 883ccd13..78644941 100644
--- a/server/streamreader/processStream.h
+++ b/server/streamreader/processStream.h
@@ -37,10 +37,10 @@ class ProcessStream : public PcmStream
 public:
     /// ctor. Encoded PCM data is passed to the PipeListener
     ProcessStream(PcmListener* pcmListener, const StreamUri& uri);
-    virtual ~ProcessStream();
+    ~ProcessStream() override;
 
-    virtual void start();
-    virtual void stop();
+    void start() override;
+    void stop() override;
 
 protected:
     std::string exe_;
@@ -50,7 +50,7 @@ protected:
     std::thread stderrReaderThread_;
     bool logStderr_;
 
-    virtual void worker();
+    void worker() override;
     virtual void stderrReader();
     virtual void onStderrMsg(const char* buffer, size_t n);
     virtual void initExeAndPath(const std::string& filename);
diff --git a/server/streamreader/spotifyStream.cpp b/server/streamreader/spotifyStream.cpp
index 4968b679..c2183e91 100644
--- a/server/streamreader/spotifyStream.cpp
+++ b/server/streamreader/spotifyStream.cpp
@@ -64,8 +64,7 @@ SpotifyStream::SpotifyStream(PcmListener* pcmListener, const StreamUri& uri) : P
 
 
 SpotifyStream::~SpotifyStream()
-{
-}
+= default;
 
 
 void SpotifyStream::initExeAndPath(const std::string& filename)
diff --git a/server/streamreader/spotifyStream.h b/server/streamreader/spotifyStream.h
index 2557c815..8fc647b4 100644
--- a/server/streamreader/spotifyStream.h
+++ b/server/streamreader/spotifyStream.h
@@ -36,16 +36,16 @@ class SpotifyStream : public ProcessStream, WatchdogListener
 public:
     /// ctor. Encoded PCM data is passed to the PipeListener
     SpotifyStream(PcmListener* pcmListener, const StreamUri& uri);
-    virtual ~SpotifyStream();
+    ~SpotifyStream() override;
 
 protected:
     std::unique_ptr<Watchdog> watchdog_;
 
-    virtual void stderrReader();
-    virtual void onStderrMsg(const char* buffer, size_t n);
-    virtual void initExeAndPath(const std::string& filename);
+    void stderrReader() override;
+    void onStderrMsg(const char* buffer, size_t n) override;
+    void initExeAndPath(const std::string& filename) override;
 
-    virtual void onTimeout(const Watchdog* watchdog, size_t ms);
+    void onTimeout(const Watchdog* watchdog, size_t ms) override;
 };