diff --git a/include/znc/Buffer.h b/include/znc/Buffer.h
index bd67ae86..59d5454a 100644
--- a/include/znc/Buffer.h
+++ b/include/znc/Buffer.h
@@ -29,7 +29,7 @@ class CClient;
 class CBufLine {
 public:
 	CBufLine() { throw 0; } // shouldn't be called, but is needed for compilation
-	CBufLine(const CString& sFormat, const CString& sText = "", const timeval* ts = 0);
+	CBufLine(const CString& sFormat, const CString& sText = "", const timeval* ts = nullptr);
 	~CBufLine();
 	CString GetLine(const CClient& Client, const MCString& msParams) const;
 	void UpdateTime();
@@ -58,7 +58,7 @@ public:
 	CBuffer(unsigned int uLineCount = 100);
 	~CBuffer();
 
-	size_type AddLine(const CString& sFormat, const CString& sText = "", const timeval* ts = 0);
+	size_type AddLine(const CString& sFormat, const CString& sText = "", const timeval* ts = nullptr);
 	/// Same as AddLine, but replaces a line whose format string starts with sMatch if there is one.
 	size_type UpdateLine(const CString& sMatch, const CString& sFormat, const CString& sText = "");
 	/// Same as UpdateLine, but does nothing if this exact line already exists.
diff --git a/include/znc/Chan.h b/include/znc/Chan.h
index 5605548e..b623a2ea 100644
--- a/include/znc/Chan.h
+++ b/include/znc/Chan.h
@@ -56,7 +56,7 @@ public:
 		M_Except     = 'e'
 	} EModes;
 
-	CChan(const CString& sName, CIRCNetwork* pNetwork, bool bInConfig, CConfig *pConfig = NULL);
+	CChan(const CString& sName, CIRCNetwork* pNetwork, bool bInConfig, CConfig *pConfig = nullptr);
 	~CChan();
 
 	CChan(const CChan&) = delete;
@@ -67,14 +67,14 @@ public:
 	void Clone(CChan& chan);
 	void Cycle() const;
 	void JoinUser(const CString& sKey = "");
-	void AttachUser(CClient* pClient = NULL);
+	void AttachUser(CClient* pClient = nullptr);
 	void DetachUser();
 
 	void OnWho(const CString& sNick, const CString& sIdent, const CString& sHost);
 
 	// Modes
 	void SetModes(const CString& s);
-	void ModeChange(const CString& sModes, const CNick* OpNick = NULL);
+	void ModeChange(const CString& sModes, const CNick* OpNick = nullptr);
 	bool AddMode(unsigned char uMode, const CString& sArg);
 	bool RemMode(unsigned char uMode);
 	CString GetModeString() const;
@@ -97,7 +97,7 @@ public:
 	unsigned int GetBufferCount() const { return m_Buffer.GetLineCount(); }
 	bool SetBufferCount(unsigned int u, bool bForce = false) { m_bHasBufferCountSet = true; return m_Buffer.SetLineCount(u, bForce); }
 	void InheritBufferCount(unsigned int u, bool bForce = false) { if (!m_bHasBufferCountSet) m_Buffer.SetLineCount(u, bForce); }
-	size_t AddBuffer(const CString& sFormat, const CString& sText = "", const timeval* ts = NULL) { return m_Buffer.AddLine(sFormat, sText, ts); }
+	size_t AddBuffer(const CString& sFormat, const CString& sText = "", const timeval* ts = nullptr) { return m_Buffer.AddLine(sFormat, sText, ts); }
 	void ClearBuffer() { m_Buffer.Clear(); }
 	void SendBuffer(CClient* pClient);
 	void SendBuffer(CClient* pClient, const CBuffer& Buffer);
diff --git a/include/znc/Client.h b/include/znc/Client.h
index 175192c6..11960761 100644
--- a/include/znc/Client.h
+++ b/include/znc/Client.h
@@ -80,7 +80,7 @@ public:
 	CClientAuth(const CClientAuth&) = delete;
 	CClientAuth& operator=(const CClientAuth&) = delete;
 
-	void Invalidate() { m_pClient = NULL; CAuthBase::Invalidate(); }
+	void Invalidate() { m_pClient = nullptr; CAuthBase::Invalidate(); }
 	void AcceptedLogin(CUser& User);
 	void RefusedLogin(const CString& sReason);
 private:
@@ -91,8 +91,8 @@ protected:
 class CClient : public CIRCSocket {
 public:
 	CClient() : CIRCSocket() {
-		m_pUser = NULL;
-		m_pNetwork = NULL;
+		m_pUser = nullptr;
+		m_pNetwork = nullptr;
 		m_bGotPass = false;
 		m_bGotNick = false;
 		m_bGotUser = false;
@@ -137,7 +137,7 @@ public:
 	void UserPortCommand(CString& sLine);
 	void StatusCTCP(const CString& sCommand);
 	void BouncedOff();
-	bool IsAttached() const { return m_pUser != NULL; }
+	bool IsAttached() const { return m_pUser != nullptr; }
 
 	bool IsPlaybackActive() const { return m_bPlaybackActive; }
 	void SetPlaybackActive(bool bActive) { m_bPlaybackActive = bActive; }
diff --git a/include/znc/FileUtils.h b/include/znc/FileUtils.h
index ce997e48..4d0b3d11 100644
--- a/include/znc/FileUtils.h
+++ b/include/znc/FileUtils.h
@@ -188,7 +188,7 @@ public:
 
 		struct dirent * de;
 
-		while ((de = readdir(dir)) != 0) {
+		while ((de = readdir(dir)) != nullptr) {
 			if ((strcmp(de->d_name, ".") == 0) || (strcmp(de->d_name, "..") == 0)) {
 				continue;
 			}
@@ -249,7 +249,7 @@ public:
 
 	static CString GetCWD() {
 		CString sRet;
-		char * pszCurDir = getcwd(NULL, 0);
+		char * pszCurDir = getcwd(nullptr, 0);
 		if (pszCurDir) {
 			sRet = pszCurDir;
 			free(pszCurDir);
diff --git a/include/znc/IRCNetwork.h b/include/znc/IRCNetwork.h
index 5f66a8fc..93ae384e 100644
--- a/include/znc/IRCNetwork.h
+++ b/include/znc/IRCNetwork.h
@@ -89,9 +89,9 @@ public:
 	const CModules& GetModules() const { return *m_pModules; }
 	// !Modules
 
-	bool PutUser(const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutStatus(const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutModule(const CString& sModule, const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
+	bool PutUser(const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutStatus(const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutModule(const CString& sModule, const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
 
 	const std::vector<CChan*>& GetChans() const;
 	CChan* FindChan(CString sName) const;
diff --git a/include/znc/Listener.h b/include/znc/Listener.h
index dc021cce..5fca2bab 100644
--- a/include/znc/Listener.h
+++ b/include/znc/Listener.h
@@ -38,7 +38,7 @@ public:
 		m_bSSL = bSSL;
 		m_eAddr = eAddr;
 		m_sURIPrefix = sURIPrefix;
-		m_pListener = NULL;
+		m_pListener = nullptr;
 		m_eAcceptType = eAccept;
 	}
 
diff --git a/include/znc/Modules.h b/include/znc/Modules.h
index 0a9ad3c3..0a2f4046 100644
--- a/include/znc/Modules.h
+++ b/include/znc/Modules.h
@@ -166,7 +166,7 @@ class CFPTimer : public CTimer {
 public:
 	CFPTimer(CModule* pModule, unsigned int uInterval, unsigned int uCycles, const CString& sLabel, const CString& sDescription)
 		: CTimer(pModule, uInterval, uCycles, sLabel, sDescription) {
-		m_pFBCallback = NULL;
+		m_pFBCallback = nullptr;
 	}
 
 	virtual ~CFPTimer() {}
@@ -221,13 +221,13 @@ public:
 	} EModuleType;
 
 	CModInfo() {
-		m_fLoader = NULL;
+		m_fLoader = nullptr;
 		m_bHasArgs = false;
 	}
 	CModInfo(const CString& sName, const CString& sPath, EModuleType eType) {
 		m_sName = sName;
 		m_sPath = sPath;
-		m_fLoader = NULL;
+		m_fLoader = nullptr;
 		m_bHasArgs = false;
 	}
 	~CModInfo() {}
diff --git a/include/znc/Query.h b/include/znc/Query.h
index b1357b40..b3f06aa9 100644
--- a/include/znc/Query.h
+++ b/include/znc/Query.h
@@ -35,7 +35,7 @@ public:
 	const CBuffer& GetBuffer() const { return m_Buffer; }
 	unsigned int GetBufferCount() const { return m_Buffer.GetLineCount(); }
 	bool SetBufferCount(unsigned int u, bool bForce = false) { return m_Buffer.SetLineCount(u, bForce); }
-	size_t AddBuffer(const CString& sFormat, const CString& sText = "", const timeval* ts = NULL) { return m_Buffer.AddLine(sFormat, sText, ts); }
+	size_t AddBuffer(const CString& sFormat, const CString& sText = "", const timeval* ts = nullptr) { return m_Buffer.AddLine(sFormat, sText, ts); }
 	void ClearBuffer() { m_Buffer.Clear(); }
 	void SendBuffer(CClient* pClient);
 	void SendBuffer(CClient* pClient, const CBuffer& Buffer);
diff --git a/include/znc/Socket.h b/include/znc/Socket.h
index 34222da5..c05325e5 100644
--- a/include/znc/Socket.h
+++ b/include/znc/Socket.h
@@ -67,7 +67,7 @@ public:
 	CSockManager();
 	virtual ~CSockManager();
 
-	bool ListenHost(u_short iPort, const CString& sSockName, const CString& sBindHost, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = NULL, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
+	bool ListenHost(u_short iPort, const CString& sSockName, const CString& sBindHost, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = nullptr, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
 		CSListener L(iPort, sBindHost);
 
 		L.SetSockName(sSockName);
@@ -92,11 +92,11 @@ public:
 		return Listen(L, pcSock);
 	}
 
-	bool ListenAll(u_short iPort, const CString& sSockName, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = NULL, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
+	bool ListenAll(u_short iPort, const CString& sSockName, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = nullptr, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
 		return ListenHost(iPort, sSockName, "", bSSL, iMaxConns, pcSock, iTimeout, eAddr);
 	}
 
-	u_short ListenRand(const CString& sSockName, const CString& sBindHost, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = NULL, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
+	u_short ListenRand(const CString& sSockName, const CString& sBindHost, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = nullptr, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
 		unsigned short uPort = 0;
 		CSListener L(0, sBindHost);
 
@@ -124,11 +124,11 @@ public:
 		return uPort;
 	}
 
-	u_short ListenAllRand(const CString& sSockName, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = NULL, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
+	u_short ListenAllRand(const CString& sSockName, bool bSSL = false, int iMaxConns = SOMAXCONN, CZNCSock *pcSock = nullptr, u_int iTimeout = 0, EAddrType eAddr = ADDR_ALL) {
 		return(ListenRand(sSockName, "", bSSL, iMaxConns, pcSock, iTimeout, eAddr));
 	}
 
-	void Connect(const CString& sHostname, u_short iPort, const CString& sSockName, int iTimeout = 60, bool bSSL = false, const CString& sBindHost = "", CZNCSock *pcSock = NULL);
+	void Connect(const CString& sHostname, u_short iPort, const CString& sSockName, int iTimeout = 60, bool bSSL = false, const CString& sBindHost = "", CZNCSock *pcSock = nullptr);
 
 	unsigned int GetAnonConnectionCount(const CString &sIP) const;
 private:
diff --git a/include/znc/Template.h b/include/znc/Template.h
index c22a9c9e..26e11e09 100644
--- a/include/znc/Template.h
+++ b/include/znc/Template.h
@@ -128,7 +128,7 @@ public:
 		Init();
 	}
 
-	CTemplate(const std::shared_ptr<CTemplateOptions>& Options, CTemplate* pParent = NULL) : MCString(), m_spOptions(Options) {
+	CTemplate(const std::shared_ptr<CTemplateOptions>& Options, CTemplate* pParent = nullptr) : MCString(), m_spOptions(Options) {
 		Init();
 		m_pParent = pParent;
 	}
diff --git a/include/znc/Threads.h b/include/znc/Threads.h
index fd98f83c..8757ab5c 100644
--- a/include/znc/Threads.h
+++ b/include/znc/Threads.h
@@ -39,7 +39,7 @@ public:
 	friend class CConditionVariable;
 
 	CMutex() {
-		int i = pthread_mutex_init(&m_mutex, NULL);
+		int i = pthread_mutex_init(&m_mutex, nullptr);
 		if (i) {
 			CUtils::PrintError("Can't initialize mutex: " + CString(strerror(errno)));
 			exit(1);
@@ -124,7 +124,7 @@ private:
 class CConditionVariable {
 public:
 	CConditionVariable() {
-		int i = pthread_cond_init(&m_cond, NULL);
+		int i = pthread_cond_init(&m_cond, nullptr);
 		if (i) {
 			CUtils::PrintError("Can't initialize condition variable: "
 					+ CString(strerror(errno)));
@@ -188,8 +188,8 @@ public:
 		 */
 		int i = sigfillset(&sigmask);
 		i |= pthread_sigmask(SIG_SETMASK, &sigmask, &old_sigmask);
-		i |= pthread_create(&thr, NULL, func, arg);
-		i |= pthread_sigmask(SIG_SETMASK, &old_sigmask, NULL);
+		i |= pthread_create(&thr, nullptr, func, arg);
+		i |= pthread_sigmask(SIG_SETMASK, &old_sigmask, nullptr);
 		i |= pthread_detach(thr);
 		if (i) {
 			CUtils::PrintError("Can't start new thread: "
@@ -295,7 +295,7 @@ private:
 	static void *threadPoolFunc(void *arg) {
 		CThreadPool &pool = *reinterpret_cast<CThreadPool *>(arg);
 		pool.threadFunc();
-		return NULL;
+		return nullptr;
 	}
 
 	// mutex protecting all of these members
diff --git a/include/znc/User.h b/include/znc/User.h
index 4b27f86c..2fd3678a 100644
--- a/include/znc/User.h
+++ b/include/znc/User.h
@@ -83,12 +83,12 @@ public:
 	bool HasSpaceForNewNetwork() const;
 	// !Networks
 
-	bool PutUser(const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutAllUser(const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutStatus(const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutStatusNotice(const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutModule(const CString& sModule, const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
-	bool PutModNotice(const CString& sModule, const CString& sLine, CClient* pClient = NULL, CClient* pSkipClient = NULL);
+	bool PutUser(const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutAllUser(const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutStatus(const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutStatusNotice(const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutModule(const CString& sModule, const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
+	bool PutModNotice(const CString& sModule, const CString& sLine, CClient* pClient = nullptr, CClient* pSkipClient = nullptr);
 
 	bool IsUserAttached() const;
 	void UserConnected(CClient* pClient);
diff --git a/include/znc/Utils.h b/include/znc/Utils.h
index 2322a8aa..b1a314ed 100644
--- a/include/znc/Utils.h
+++ b/include/znc/Utils.h
@@ -65,13 +65,13 @@ public:
 	static CString GetPass(const CString& sPrompt);
 	static bool GetInput(const CString& sPrompt, CString& sRet, const CString& sDefault = "", const CString& sHint = "");
 	static bool GetBoolInput(const CString& sPrompt, bool bDefault);
-	static bool GetBoolInput(const CString& sPrompt, bool *pbDefault = NULL);
+	static bool GetBoolInput(const CString& sPrompt, bool *pbDefault = nullptr);
 	static bool GetNumInput(const CString& sPrompt, unsigned int& uRet, unsigned int uMin = 0, unsigned int uMax = ~0, unsigned int uDefault = ~0);
 
 	static unsigned long long GetMillTime() {
 		struct timeval tv;
 		unsigned long long iTime = 0;
-		gettimeofday(&tv, NULL);
+		gettimeofday(&tv, nullptr);
 		iTime = (unsigned long long) tv.tv_sec * 1000;
 		iTime += ((unsigned long long) tv.tv_usec / 1000);
 		return iTime;
@@ -318,7 +318,7 @@ public:
 		Cleanup();
 		iterator it = m_mItems.find(Item);
 		if (it == m_mItems.end())
-			return NULL;
+			return nullptr;
 		return &it->second.second;
 	}
 
diff --git a/include/znc/WebModules.h b/include/znc/WebModules.h
index bd860ef8..5a8c4bb5 100644
--- a/include/znc/WebModules.h
+++ b/include/znc/WebModules.h
@@ -54,7 +54,7 @@ public:
 	const CString& GetIP() const { return m_sIP; }
 	CUser* GetUser() const { return m_pUser; }
 	time_t GetLastActive() const { return m_tmLastActive; }
-	bool IsLoggedIn() const { return m_pUser != NULL; }
+	bool IsLoggedIn() const { return m_pUser != nullptr; }
 	bool IsAdmin() const;
 	void UpdateLastActive();
 
@@ -128,8 +128,8 @@ public:
 	bool OnLogin(const CString& sUser, const CString& sPass, bool bBasic) override;
 	void OnPageRequest(const CString& sURI) override;
 
-	EPageReqResult PrintTemplate(const CString& sPageName, CString& sPageRet, CModule* pModule = NULL);
-	EPageReqResult PrintStaticFile(const CString& sPath, CString& sPageRet, CModule* pModule = NULL);
+	EPageReqResult PrintTemplate(const CString& sPageName, CString& sPageRet, CModule* pModule = nullptr);
+	EPageReqResult PrintStaticFile(const CString& sPath, CString& sPageRet, CModule* pModule = nullptr);
 
 	CString FindTmpl(CModule* pModule, const CString& sName);
 
@@ -150,7 +150,7 @@ public:
 protected:
 	using CHTTPSock::PrintErrorPage;
 
-	bool AddModLoop(const CString& sLoopName, CModule& Module, CTemplate *pTemplate = NULL);
+	bool AddModLoop(const CString& sLoopName, CModule& Module, CTemplate *pTemplate = nullptr);
 	VCString GetDirs(CModule* pModule, bool bIsTemplate);
 	void SetPaths(CModule* pModule, bool bIsTemplate = false);
 	void SetVars();
diff --git a/include/znc/ZNCString.h b/include/znc/ZNCString.h
index 2b29f0fb..8b853002 100644
--- a/include/znc/ZNCString.h
+++ b/include/znc/ZNCString.h
@@ -564,7 +564,7 @@ public:
 
 private:
 protected:
-	unsigned char* strnchr(const unsigned char* src, unsigned char c, unsigned int iMaxBytes, unsigned char* pFill = NULL, unsigned int* piCount = NULL) const;
+	unsigned char* strnchr(const unsigned char* src, unsigned char c, unsigned int iMaxBytes, unsigned char* pFill = nullptr, unsigned int* piCount = nullptr) const;
 };
 
 /**
diff --git a/include/znc/znc.h b/include/znc/znc.h
index 7622f8d4..05fad412 100644
--- a/include/znc/znc.h
+++ b/include/znc/znc.h
@@ -74,7 +74,7 @@ public:
 	bool AddTrustedProxy(const CString& sHost);
 	bool RemTrustedProxy(const CString& sHost);
 	void Broadcast(const CString& sMessage, bool bAdminOnly = false,
-			CUser* pSkipUser = NULL, CClient* pSkipClient = NULL);
+			CUser* pSkipUser = nullptr, CClient* pSkipClient = nullptr);
 	void AddBytesRead(unsigned long long u) { m_uBytesRead += u; }
 	void AddBytesWritten(unsigned long long u) { m_uBytesWritten += u; }
 	unsigned long long BytesRead() const { return m_uBytesRead; }
diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index 10df96ea..69c35e50 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -20,7 +20,7 @@
 CBufLine::CBufLine(const CString& sFormat, const CString& sText, const timeval* ts) {
 	m_sFormat = sFormat;
 	m_sText = sText;
-	if (ts == NULL)
+	if (ts == nullptr)
 		UpdateTime();
 	else
 		m_time = *ts;
@@ -29,10 +29,10 @@ CBufLine::CBufLine(const CString& sFormat, const CString& sText, const timeval*
 CBufLine::~CBufLine() {}
 
 void CBufLine::UpdateTime() {
-	if (0 == gettimeofday(&m_time, NULL)) {
+	if (0 == gettimeofday(&m_time, nullptr)) {
 		return;
 	}
-	m_time.tv_sec = time(NULL);
+	m_time.tv_sec = time(nullptr);
 	m_time.tv_usec = 0;
 }
 
diff --git a/src/Chan.cpp b/src/Chan.cpp
index a35afe38..63f12d83 100644
--- a/src/Chan.cpp
+++ b/src/Chan.cpp
@@ -293,7 +293,7 @@ void CChan::ModeChange(const CString& sModes, const CNick* pOpNick) {
 			pOpNick = OpNick;
 	}
 
-	NETWORKMODULECALL(OnRawMode2(pOpNick, *this, sModeArg, sArgs), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+	NETWORKMODULECALL(OnRawMode2(pOpNick, *this, sModeArg, sArgs), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 
 	for (unsigned int a = 0; a < sModeArg.size(); a++) {
 		const unsigned char& uMode = sModeArg[a];
@@ -325,19 +325,19 @@ void CChan::ModeChange(const CString& sModes, const CNick* pOpNick) {
 						}
 					}
 
-					NETWORKMODULECALL(OnChanPermission2(pOpNick, *pNick, *this, uMode, bAdd, bNoChange), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+					NETWORKMODULECALL(OnChanPermission2(pOpNick, *pNick, *this, uMode, bAdd, bNoChange), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 
 					if (uMode == CChan::M_Op) {
 						if (bAdd) {
-							NETWORKMODULECALL(OnOp2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+							NETWORKMODULECALL(OnOp2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 						} else {
-							NETWORKMODULECALL(OnDeop2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+							NETWORKMODULECALL(OnDeop2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 						}
 					} else if (uMode == CChan::M_Voice) {
 						if (bAdd) {
-							NETWORKMODULECALL(OnVoice2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+							NETWORKMODULECALL(OnVoice2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 						} else {
-							NETWORKMODULECALL(OnDevoice2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+							NETWORKMODULECALL(OnDevoice2(pOpNick, *pNick, *this, bNoChange), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 						}
 					}
 				}
@@ -372,7 +372,7 @@ void CChan::ModeChange(const CString& sModes, const CNick* pOpNick) {
 			} else {
 				bNoChange = !HasMode(uMode);
 			}
-			NETWORKMODULECALL(OnMode2(pOpNick, *this, uMode, sArg, bAdd, bNoChange), m_pNetwork->GetUser(), m_pNetwork, NULL, NOTHING);
+			NETWORKMODULECALL(OnMode2(pOpNick, *this, uMode, sArg, bAdd, bNoChange), m_pNetwork->GetUser(), m_pNetwork, nullptr, NOTHING);
 
 			if (!bList) {
 				(bAdd) ? AddMode(uMode, sArg) : RemMode(uMode);
@@ -566,12 +566,12 @@ bool CChan::ChangeNick(const CString& sOldNick, const CString& sNewNick) {
 
 const CNick* CChan::FindNick(const CString& sNick) const {
 	map<CString,CNick>::const_iterator it = m_msNicks.find(sNick);
-	return (it != m_msNicks.end()) ? &it->second : NULL;
+	return (it != m_msNicks.end()) ? &it->second : nullptr;
 }
 
 CNick* CChan::FindNick(const CString& sNick) {
 	map<CString,CNick>::iterator it = m_msNicks.find(sNick);
-	return (it != m_msNicks.end()) ? &it->second : NULL;
+	return (it != m_msNicks.end()) ? &it->second : nullptr;
 }
 
 void CChan::SendBuffer(CClient* pClient) {
@@ -606,7 +606,7 @@ void CChan::SendBuffer(CClient* pClient, const CBuffer& Buffer) {
 				pUseClient->SetPlaybackActive(true);
 
 				bool bSkipStatusMsg = pUseClient->HasServerTime();
-				NETWORKMODULECALL(OnChanBufferStarting(*this, *pUseClient), m_pNetwork->GetUser(), m_pNetwork, NULL, &bSkipStatusMsg);
+				NETWORKMODULECALL(OnChanBufferStarting(*this, *pUseClient), m_pNetwork->GetUser(), m_pNetwork, nullptr, &bSkipStatusMsg);
 
 				if (!bSkipStatusMsg) {
 					m_pNetwork->PutUser(":***!znc@znc.in PRIVMSG " + GetName() + " :Buffer Playback...", pUseClient);
@@ -629,13 +629,13 @@ void CChan::SendBuffer(CClient* pClient, const CBuffer& Buffer) {
 						CUtils::SetMessageTags(sLine, msBatchTags);
 					}
 					bool bNotShowThisLine = false;
-					NETWORKMODULECALL(OnChanBufferPlayLine2(*this, *pUseClient, sLine, BufLine.GetTime()), m_pNetwork->GetUser(), m_pNetwork, NULL, &bNotShowThisLine);
+					NETWORKMODULECALL(OnChanBufferPlayLine2(*this, *pUseClient, sLine, BufLine.GetTime()), m_pNetwork->GetUser(), m_pNetwork, nullptr, &bNotShowThisLine);
 					if (bNotShowThisLine) continue;
 					m_pNetwork->PutUser(sLine, pUseClient);
 				}
 
 				bSkipStatusMsg = pUseClient->HasServerTime();
-				NETWORKMODULECALL(OnChanBufferEnding(*this, *pUseClient), m_pNetwork->GetUser(), m_pNetwork, NULL, &bSkipStatusMsg);
+				NETWORKMODULECALL(OnChanBufferEnding(*this, *pUseClient), m_pNetwork->GetUser(), m_pNetwork, nullptr, &bSkipStatusMsg);
 				if (!bSkipStatusMsg) {
 					m_pNetwork->PutUser(":***!znc@znc.in PRIVMSG " + GetName() + " :Playback Complete.", pUseClient);
 				}
diff --git a/src/Client.cpp b/src/Client.cpp
index b9377daa..6b5aae19 100644
--- a/src/Client.cpp
+++ b/src/Client.cpp
@@ -72,7 +72,7 @@ CClient::~CClient() {
 		CClientAuth* pAuth = (CClientAuth*) &(*m_spAuth);
 		pAuth->Invalidate();
 	}
-	if (m_pUser != NULL) {
+	if (m_pUser != nullptr) {
 		m_pUser->AddBytesRead(GetBytesRead());
 		m_pUser->AddBytesWritten(GetBytesWritten());
 	}
@@ -579,7 +579,7 @@ const CIRCSock* CClient::GetIRCSock() const {
 		return m_pNetwork->GetIRCSock();
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 CIRCSock* CClient::GetIRCSock() {
@@ -587,7 +587,7 @@ CIRCSock* CClient::GetIRCSock() {
 		return m_pNetwork->GetIRCSock();
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 void CClient::StatusCTCP(const CString& sLine) {
@@ -645,7 +645,7 @@ CString CAuthBase::GetRemoteIP() const {
 }
 
 void CAuthBase::Invalidate() {
-	m_pSock = NULL;
+	m_pSock = nullptr;
 }
 
 void CAuthBase::AcceptLogin(CUser& User) {
@@ -740,7 +740,7 @@ void CClient::ConnectionRefused() {
 void CClient::Disconnected() {
 	DEBUG(GetSockName() << " == Disconnected()");
 	CIRCNetwork* pNetwork = m_pNetwork;
-	SetNetwork(NULL, true, false);
+	SetNetwork(nullptr, true, false);
 
 	if (m_pUser) {
 		NETWORKMODULECALL(OnClientDisconnect(), m_pUser, pNetwork, this, NOTHING);
diff --git a/src/ClientCommand.cpp b/src/ClientCommand.cpp
index a9e92677..78f67115 100644
--- a/src/ClientCommand.cpp
+++ b/src/ClientCommand.cpp
@@ -312,7 +312,7 @@ void CClient::UserCommand(CString& sLine) {
 
 		CString sArgs = sLine.Token(1, true);
 		sArgs.Trim();
-		CServer *pServer = NULL;
+		CServer *pServer = nullptr;
 
 		if (!sArgs.empty()) {
 			pServer = m_pNetwork->FindServer(sArgs);
@@ -539,7 +539,7 @@ void CClient::UserCommand(CString& sLine) {
 		}
 
 		if (m_pNetwork && m_pNetwork->GetName().Equals(sNetwork)) {
-			SetNetwork(NULL);
+			SetNetwork(nullptr);
 		}
 
 		if (m_pUser->DeleteNetwork(sNetwork)) {
@@ -659,7 +659,7 @@ void CClient::UserCommand(CString& sLine) {
 		pNewNetwork->Clone(*pOldNetwork, false);
 
 		if (m_pNetwork && m_pNetwork->GetName().Equals(sOldNetwork) && m_pUser == pOldUser) {
-			SetNetwork(NULL);
+			SetNetwork(nullptr);
 		}
 
 		if (pOldUser->DeleteNetwork(sOldNetwork)) {
@@ -1003,10 +1003,10 @@ void CClient::UserCommand(CString& sLine) {
 
 		switch (eType) {
 		case CModInfo::GlobalModule:
-			b = CZNC::Get().GetModules().LoadModule(sMod, sArgs, eType, NULL, NULL, sModRet);
+			b = CZNC::Get().GetModules().LoadModule(sMod, sArgs, eType, nullptr, nullptr, sModRet);
 			break;
 		case CModInfo::UserModule:
-			b = m_pUser->GetModules().LoadModule(sMod, sArgs, eType, m_pUser, NULL, sModRet);
+			b = m_pUser->GetModules().LoadModule(sMod, sArgs, eType, m_pUser, nullptr, sModRet);
 			break;
 		case CModInfo::NetworkModule:
 				b = m_pNetwork->GetModules().LoadModule(sMod, sArgs, eType, m_pUser, m_pNetwork, sModRet);
@@ -1142,10 +1142,10 @@ void CClient::UserCommand(CString& sLine) {
 
 		switch (eType) {
 		case CModInfo::GlobalModule:
-			CZNC::Get().GetModules().ReloadModule(sMod, sArgs, NULL, NULL, sModRet);
+			CZNC::Get().GetModules().ReloadModule(sMod, sArgs, nullptr, nullptr, sModRet);
 			break;
 		case CModInfo::UserModule:
-			m_pUser->GetModules().ReloadModule(sMod, sArgs, m_pUser, NULL, sModRet);
+			m_pUser->GetModules().ReloadModule(sMod, sArgs, m_pUser, nullptr, sModRet);
 			break;
 		case CModInfo::NetworkModule:
 			m_pNetwork->GetModules().ReloadModule(sMod, sArgs, m_pUser, m_pNetwork, sModRet);
diff --git a/src/Config.cpp b/src/Config.cpp
index 680566da..8dcade20 100644
--- a/src/Config.cpp
+++ b/src/Config.cpp
@@ -31,7 +31,7 @@ struct ConfigStackEntry {
 };
 
 CConfigEntry::CConfigEntry()
-	: m_pSubConfig(NULL) {
+	: m_pSubConfig(nullptr) {
 }
 
 CConfigEntry::CConfigEntry(const CConfig& Config)
@@ -39,7 +39,7 @@ CConfigEntry::CConfigEntry(const CConfig& Config)
 }
 
 CConfigEntry::CConfigEntry(const CConfigEntry& other)
-	: m_pSubConfig(NULL) {
+	: m_pSubConfig(nullptr) {
 	if (other.m_pSubConfig)
 		m_pSubConfig = new CConfig(*other.m_pSubConfig);
 }
@@ -54,7 +54,7 @@ CConfigEntry& CConfigEntry::operator=(const CConfigEntry& other) {
 	if (other.m_pSubConfig)
 		m_pSubConfig = new CConfig(*other.m_pSubConfig);
 	else
-		m_pSubConfig = NULL;
+		m_pSubConfig = nullptr;
 	return *this;
 }
 
diff --git a/src/FileUtils.cpp b/src/FileUtils.cpp
index b1aa3112..f406688b 100644
--- a/src/FileUtils.cpp
+++ b/src/FileUtils.cpp
@@ -648,7 +648,7 @@ int CExecSock::popen2(int & iReadFD, int & iWriteFD, const CString & sCommand) {
 			"sh",
 			"-c",
 			sCommand.c_str(),
-			NULL
+			nullptr
 		};
 		execvp("sh", (char * const *) pArgv);
 		// if execvp returns, there was an error
@@ -668,9 +668,9 @@ int CExecSock::popen2(int & iReadFD, int & iWriteFD, const CString & sCommand) {
 void CExecSock::close2(int iPid, int iReadFD, int iWriteFD) {
 	close(iReadFD);
 	close(iWriteFD);
-	time_t iNow = time(NULL);
-	while (waitpid(iPid, NULL, WNOHANG) == 0) {
-		if ((time(NULL) - iNow) > 5)
+	time_t iNow = time(nullptr);
+	while (waitpid(iPid, nullptr, WNOHANG) == 0) {
+		if ((time(nullptr) - iNow) > 5)
 			break;  // giveup
 		usleep(100);
 	}
diff --git a/src/IRCNetwork.cpp b/src/IRCNetwork.cpp
index 372e8a30..9c0b06f0 100644
--- a/src/IRCNetwork.cpp
+++ b/src/IRCNetwork.cpp
@@ -109,13 +109,13 @@ bool CIRCNetwork::IsValidNetwork(const CString& sNetwork) {
 }
 
 CIRCNetwork::CIRCNetwork(CUser *pUser, const CString& sName) {
-	m_pUser = NULL;
+	m_pUser = nullptr;
 	SetUser(pUser);
 	m_sName = sName;
 
 	m_pModules = new CModules;
 
-	m_pIRCSock = NULL;
+	m_pIRCSock = nullptr;
 	m_uServerIdx = 0;
 
 	m_sChanPrefixes = "";
@@ -143,12 +143,12 @@ CIRCNetwork::CIRCNetwork(CUser *pUser, const CString& sName) {
 }
 
 CIRCNetwork::CIRCNetwork(CUser *pUser, const CIRCNetwork &Network) {
-	m_pUser = NULL;
+	m_pUser = nullptr;
 	SetUser(pUser);
 
 	m_pModules = new CModules;
 
-	m_pIRCSock = NULL;
+	m_pIRCSock = nullptr;
 	m_uServerIdx = 0;
 
 	m_sChanPrefixes = "";
@@ -278,7 +278,7 @@ void CIRCNetwork::Clone(const CIRCNetwork& Network, bool bCloneName) {
 CIRCNetwork::~CIRCNetwork() {
 	if (m_pIRCSock) {
 		CZNC::Get().GetManager().DelSockByAddr(m_pIRCSock);
-		m_pIRCSock = NULL;
+		m_pIRCSock = nullptr;
 	}
 
 	// Delete clients
@@ -292,7 +292,7 @@ CIRCNetwork::~CIRCNetwork() {
 
 	// Delete modules (this unloads all modules)
 	delete m_pModules;
-	m_pModules = NULL;
+	m_pModules = nullptr;
 
 	// Delete Channels
 	for (vector<CChan*>::const_iterator it = m_vChans.begin(); it != m_vChans.end(); ++it) {
@@ -306,7 +306,7 @@ CIRCNetwork::~CIRCNetwork() {
 	}
 	m_vQueries.clear();
 
-	SetUser(NULL);
+	SetUser(nullptr);
 
 	// Make sure we are not in the connection queue
 	CZNC::Get().GetConnectionQueue().remove(this);
@@ -617,7 +617,7 @@ void CIRCNetwork::ClientConnected(CClient *pClient) {
 		}
  	}
 
-	if (GetIRCSock() != NULL) {
+	if (GetIRCSock() != nullptr) {
 		CString sUserMode("");
 		const set<unsigned char>& scUserModes = GetIRCSock()->GetUserModes();
 		for (set<unsigned char>::const_iterator it = scUserModes.begin();
@@ -658,7 +658,7 @@ void CIRCNetwork::ClientConnected(CClient *pClient) {
 		const CBufLine& BufLine = m_NoticeBuffer.GetBufLine(uIdx);
 		CString sLine = BufLine.GetLine(*pClient, msParams);
 		bool bContinue = false;
-		NETWORKMODULECALL(OnPrivBufferPlayLine2(*pClient, sLine, BufLine.GetTime()), m_pUser, this, NULL, &bContinue);
+		NETWORKMODULECALL(OnPrivBufferPlayLine2(*pClient, sLine, BufLine.GetTime()), m_pUser, this, nullptr, &bContinue);
 		if (bContinue) continue;
 		pClient->PutClient(sLine);
 	}
@@ -703,7 +703,7 @@ std::vector<CClient*> CIRCNetwork::FindClients(const CString& sIdentifier) const
 void CIRCNetwork::SetUser(CUser *pUser) {
 	for (unsigned int a = 0; a < m_vClients.size(); a++) {
 		m_vClients[a]->PutStatus("This network is being deleted or moved to another user.");
-		m_vClients[a]->SetNetwork(NULL);
+		m_vClients[a]->SetNetwork(nullptr);
 	}
 
 	m_vClients.clear();
@@ -738,7 +738,7 @@ bool CIRCNetwork::PutUser(const CString& sLine, CClient* pClient, CClient* pSkip
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CIRCNetwork::PutStatus(const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -752,7 +752,7 @@ bool CIRCNetwork::PutStatus(const CString& sLine, CClient* pClient, CClient* pSk
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CIRCNetwork::PutModule(const CString& sModule, const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -766,7 +766,7 @@ bool CIRCNetwork::PutModule(const CString& sModule, const CString& sLine, CClien
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 // Channels
@@ -786,7 +786,7 @@ CChan* CIRCNetwork::FindChan(CString sName) const {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 std::vector<CChan*> CIRCNetwork::FindChans(const CString& sWild) const {
@@ -907,7 +907,7 @@ void CIRCNetwork::JoinChans(set<CChan*>& sChans) {
 
 bool CIRCNetwork::JoinChan(CChan* pChan) {
 	bool bReturn = false;
-	NETWORKMODULECALL(OnJoining(*pChan), m_pUser, this, NULL, &bReturn);
+	NETWORKMODULECALL(OnJoining(*pChan), m_pUser, this, nullptr, &bReturn);
 
 	if (bReturn)
 		return false;
@@ -918,7 +918,7 @@ bool CIRCNetwork::JoinChan(CChan* pChan) {
 	} else {
 		pChan->IncJoinTries();
 		bool bFailed = false;
-		NETWORKMODULECALL(OnTimerAutoJoin(*pChan), m_pUser, this, NULL, &bFailed);
+		NETWORKMODULECALL(OnTimerAutoJoin(*pChan), m_pUser, this, nullptr, &bFailed);
 		if (bFailed) return false;
 		return true;
 	}
@@ -946,7 +946,7 @@ CQuery* CIRCNetwork::FindQuery(const CString& sName) const {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 std::vector<CQuery*> CIRCNetwork::FindQueries(const CString& sWild) const {
@@ -962,7 +962,7 @@ std::vector<CQuery*> CIRCNetwork::FindQueries(const CString& sWild) const {
 
 CQuery* CIRCNetwork::AddQuery(const CString& sName) {
 	if (sName.empty()) {
-		return NULL;
+		return nullptr;
 	}
 
 	CQuery* pQuery = FindQuery(sName);
@@ -1005,7 +1005,7 @@ CServer* CIRCNetwork::FindServer(const CString& sName) const {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 bool CIRCNetwork::DelServer(const CString& sName, unsigned short uPort, const CString& sPass) {
@@ -1129,7 +1129,7 @@ bool CIRCNetwork::AddServer(const CString& sName, unsigned short uPort, const CS
 
 CServer* CIRCNetwork::GetNextServer() {
 	if (m_vServers.empty()) {
-		return NULL;
+		return nullptr;
 	}
 
 	if (m_uServerIdx >= m_vServers.size()) {
@@ -1143,7 +1143,7 @@ CServer* CIRCNetwork::GetCurrentServer() const {
 	size_t uIdx = (m_uServerIdx) ? m_uServerIdx -1 : 0;
 
 	if (uIdx >= m_vServers.size()) {
-		return NULL;
+		return nullptr;
 	}
 
 	return m_vServers[uIdx];
@@ -1223,7 +1223,7 @@ bool CIRCNetwork::Connect() {
 	DEBUG("Connecting user/network [" << m_pUser->GetUserName() << "/" << m_sName << "]");
 
 	bool bAbort = false;
-	NETWORKMODULECALL(OnIRCConnecting(pIRCSock), m_pUser, this, NULL, &bAbort);
+	NETWORKMODULECALL(OnIRCConnecting(pIRCSock), m_pUser, this, nullptr, &bAbort);
 	if (bAbort) {
 		DEBUG("Some module aborted the connection attempt");
 		PutStatus("Some module aborted the connection attempt");
@@ -1256,7 +1256,7 @@ void CIRCNetwork::IRCConnected() {
 }
 
 void CIRCNetwork::IRCDisconnected() {
-	m_pIRCSock = NULL;
+	m_pIRCSock = nullptr;
 
 	SetIRCServer("");
 	m_bIRCAway = false;
@@ -1281,7 +1281,7 @@ void CIRCNetwork::SetIRCConnectEnabled(bool b) {
 
 void CIRCNetwork::CheckIRCConnect() {
 	// Do we want to connect?
-	if (GetIRCConnectEnabled() && GetIRCSock() == NULL)
+	if (GetIRCConnectEnabled() && GetIRCSock() == nullptr)
 		CZNC::Get().AddNetworkToQueue(this);
 }
 
diff --git a/src/IRCSock.cpp b/src/IRCSock.cpp
index a51db0f4..105d3d8a 100644
--- a/src/IRCSock.cpp
+++ b/src/IRCSock.cpp
@@ -736,7 +736,7 @@ void CIRCSock::ReadLine(const CString& sData) {
 				if (bReturn) return;
 
 				pChan->SetTopicOwner(Nick.GetNick());
-				pChan->SetTopicDate((unsigned long) time(NULL));
+				pChan->SetTopicDate((unsigned long) time(nullptr));
 				pChan->SetTopic(sTopic);
 
 				if (pChan->IsDetached()) {
@@ -954,7 +954,7 @@ bool CIRCSock::OnGeneralCTCP(CNick& Nick, CString& sMessage) {
 	}
 
 	if (!sReply.empty()) {
-		time_t now = time(NULL);
+		time_t now = time(nullptr);
 		// If the last CTCP is older than m_uCTCPFloodTime, reset the counter
 		if (m_lastCTCP + m_uCTCPFloodTime < now)
 			m_uNumCTCP = 0;
diff --git a/src/Listener.cpp b/src/Listener.cpp
index 4fc9eddb..bb067d16 100644
--- a/src/Listener.cpp
+++ b/src/Listener.cpp
@@ -46,7 +46,7 @@ bool CListener::Listen() {
 }
 
 void CListener::ResetRealListener() {
-	m_pListener = NULL;
+	m_pListener = nullptr;
 }
 
 CRealListener::~CRealListener() {
@@ -114,7 +114,7 @@ void CIncomingConnection::ReadLine(const CString& sLine) {
 		|| (m_eAcceptType == CListener::ACCEPT_HTTP);
 	bool bAcceptIRC = (m_eAcceptType == CListener::ACCEPT_ALL)
 		|| (m_eAcceptType == CListener::ACCEPT_IRC);
-	Csock *pSock = NULL;
+	Csock *pSock = nullptr;
 
 	if (!bIsHTTP) {
 		// Let's assume it's an IRC connection
diff --git a/src/Modules.cpp b/src/Modules.cpp
index 55a1a311..544a1372 100644
--- a/src/Modules.cpp
+++ b/src/Modules.cpp
@@ -133,7 +133,7 @@ CModule::CModule(ModHandle pDLL, CUser* pUser, CIRCNetwork* pNetwork, const CStr
 	m_pManager = &(CZNC::Get().GetManager());;
 	m_pUser = pUser;
 	m_pNetwork = pNetwork;
-	m_pClient = NULL;
+	m_pClient = nullptr;
 	m_sModName = sModName;
 	m_sDataDir = sDataDir;
 
@@ -330,7 +330,7 @@ bool CModule::UnlinkTimer(CTimer* pTimer) {
 
 CTimer* CModule::FindTimer(const CString& sLabel) {
 	if (sLabel.empty()) {
-		return NULL;
+		return nullptr;
 	}
 
 	set<CTimer*>::iterator it;
@@ -341,7 +341,7 @@ CTimer* CModule::FindTimer(const CString& sLabel) {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 void CModule::ListTimers() {
@@ -430,7 +430,7 @@ CSocket* CModule::FindSocket(const CString& sSockName) {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 void CModule::ListSockets() {
@@ -483,7 +483,7 @@ void CModule::AddJob(CModuleJob *pJob)
 
 void CModule::CancelJob(CModuleJob *pJob)
 {
-	if (pJob == NULL)
+	if (pJob == nullptr)
 		return;
 	// Destructor calls UnlinkJob and removes the job from m_sJobs
 	CThreadPool::Get().cancelJob(pJob);
@@ -517,11 +517,11 @@ bool CModule::UnlinkJob(CModuleJob *pJob)
 
 bool CModule::AddCommand(const CModCommand& Command)
 {
-	if (Command.GetFunction() == NULL)
+	if (Command.GetFunction() == nullptr)
 		return false;
 	if (Command.GetCommand().find(' ') != CString::npos)
 		return false;
-	if (FindCommand(Command.GetCommand()) != NULL)
+	if (FindCommand(Command.GetCommand()) != nullptr)
 		return false;
 
 	m_mCommands[Command.GetCommand()] = Command;
@@ -557,7 +557,7 @@ const CModCommand* CModule::FindCommand(const CString& sCmd) const
 			continue;
 		return &it->second;
 	}
-	return NULL;
+	return nullptr;
 }
 
 bool CModule::HandleCommand(const CString& sLine) {
@@ -785,9 +785,9 @@ void CModule::OnGetAvailableMods(set<CModInfo>& ssMods, CModInfo::EModuleType eT
 
 
 CModules::CModules() {
-	m_pUser = NULL;
-	m_pNetwork = NULL;
-	m_pClient = NULL;
+	m_pUser = nullptr;
+	m_pNetwork = nullptr;
+	m_pClient = nullptr;
 }
 
 CModules::~CModules() {
@@ -1012,20 +1012,20 @@ CModule* CModules::FindModule(const CString& sModule) const {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 bool CModules::LoadModule(const CString& sModule, const CString& sArgs, CModInfo::EModuleType eType, CUser* pUser, CIRCNetwork *pNetwork, CString& sRetMsg) {
 	sRetMsg = "";
 
-	if (FindModule(sModule) != NULL) {
+	if (FindModule(sModule) != nullptr) {
 		sRetMsg = "Module [" + sModule + "] already loaded.";
 		return false;
 	}
 
 	bool bSuccess;
 	bool bHandled = false;
-	_GLOBALMODULECALL(OnModuleLoading(sModule, sArgs, eType, bSuccess, sRetMsg), pUser, pNetwork, NULL, &bHandled);
+	_GLOBALMODULECALL(OnModuleLoading(sModule, sArgs, eType, bSuccess, sRetMsg), pUser, pNetwork, nullptr, &bHandled);
 	if (bHandled) return bSuccess;
 
 	CString sModPath, sDataPath;
@@ -1115,7 +1115,7 @@ bool CModules::UnloadModule(const CString& sModule, CString& sRetMsg) {
 
 	bool bSuccess;
 	bool bHandled = false;
-	_GLOBALMODULECALL(OnModuleUnloading(pModule, bSuccess, sRetMsg), pModule->GetUser(), pModule->GetNetwork(), NULL, &bHandled);
+	_GLOBALMODULECALL(OnModuleUnloading(pModule, bSuccess, sRetMsg), pModule->GetUser(), pModule->GetNetwork(), nullptr, &bHandled);
 	if (bHandled) return bSuccess;
 
 	ModHandle p = pModule->GetDLL();
@@ -1150,7 +1150,7 @@ bool CModules::ReloadModule(const CString& sModule, const CString& sArgs, CUser*
 	}
 
 	CModInfo::EModuleType eType = pModule->GetType();
-	pModule = NULL;
+	pModule = nullptr;
 
 	sRetMsg = "";
 	if (!UnloadModule(sMod, sRetMsg)) {
@@ -1306,7 +1306,7 @@ ModHandle CModules::OpenModule(const CString& sModule, const CString& sModPath,
 	for (unsigned int a = 0; a < sModule.length(); a++) {
 		if (((sModule[a] < '0') || (sModule[a] > '9')) && ((sModule[a] < 'a') || (sModule[a] > 'z')) && ((sModule[a] < 'A') || (sModule[a] > 'Z')) && (sModule[a] != '_')) {
 			sRetMsg = "Module names can only contain letters, numbers and underscores, [" + sModule + "] is invalid.";
-			return NULL;
+			return nullptr;
 		}
 	}
 
@@ -1330,7 +1330,7 @@ ModHandle CModules::OpenModule(const CString& sModule, const CString& sModPath,
 		const char* cDlError = dlerror();
 		CString sDlError = cDlError ? cDlError : "Unknown error";
 		sRetMsg = "Unable to open module [" + sModule + "] [" + sDlError + "]";
-		return NULL;
+		return nullptr;
 	}
 
 	typedef bool (*InfoFP)(double, CModInfo&);
@@ -1339,7 +1339,7 @@ ModHandle CModules::OpenModule(const CString& sModule, const CString& sModPath,
 	if (!ZNCModInfo) {
 		dlclose(p);
 		sRetMsg = "Could not find ZNCModInfo() in module [" + sModule + "]";
-		return NULL;
+		return nullptr;
 	}
 
 	if (ZNCModInfo(CModule::GetCoreVersion(), Info)) {
@@ -1354,7 +1354,7 @@ ModHandle CModules::OpenModule(const CString& sModule, const CString& sModPath,
 }
 
 CModCommand::CModCommand()
-	: m_sCmd(), m_pFunc(NULL), m_sArgs(), m_sDesc()
+	: m_sCmd(), m_pFunc(nullptr), m_sArgs(), m_sDesc()
 {
 }
 
diff --git a/src/Nick.cpp b/src/Nick.cpp
index ec92c300..32a51f09 100644
--- a/src/Nick.cpp
+++ b/src/Nick.cpp
@@ -34,7 +34,7 @@ CNick::~CNick() {}
 
 void CNick::Reset() {
 	m_sChanPerms.clear();
-	m_pNetwork = NULL;
+	m_pNetwork = nullptr;
 }
 
 void CNick::Parse(const CString& sNickMask) {
@@ -115,7 +115,7 @@ bool CNick::RemPerm(unsigned char uPerm) {
 }
 
 unsigned char CNick::GetPermChar() const {
-	CIRCSock* pIRCSock = (!m_pNetwork) ? NULL : m_pNetwork->GetIRCSock();
+	CIRCSock* pIRCSock = (!m_pNetwork) ? nullptr : m_pNetwork->GetIRCSock();
 	const CString& sChanPerms = (!pIRCSock) ? "@+" : pIRCSock->GetPerms();
 
 	for (unsigned int a = 0; a < sChanPerms.size(); a++) {
@@ -129,7 +129,7 @@ unsigned char CNick::GetPermChar() const {
 }
 
 CString CNick::GetPermStr() const {
-	CIRCSock* pIRCSock = (!m_pNetwork) ? NULL : m_pNetwork->GetIRCSock();
+	CIRCSock* pIRCSock = (!m_pNetwork) ? nullptr : m_pNetwork->GetIRCSock();
 	const CString& sChanPerms = (!pIRCSock) ? "@+" : pIRCSock->GetPerms();
 	CString sRet;
 
diff --git a/src/Query.cpp b/src/Query.cpp
index 9ba8c9e9..c59895ee 100644
--- a/src/Query.cpp
+++ b/src/Query.cpp
@@ -73,7 +73,7 @@ void CQuery::SendBuffer(CClient* pClient, const CBuffer& Buffer) {
 						CUtils::SetMessageTags(sLine, msBatchTags);
 					}
 					bool bContinue = false;
-					NETWORKMODULECALL(OnPrivBufferPlayLine2(*pUseClient, sLine, BufLine.GetTime()), m_pNetwork->GetUser(), m_pNetwork, NULL, &bContinue);
+					NETWORKMODULECALL(OnPrivBufferPlayLine2(*pUseClient, sLine, BufLine.GetTime()), m_pNetwork->GetUser(), m_pNetwork, nullptr, &bContinue);
 					if (bContinue) continue;
 					m_pNetwork->PutUser(sLine, pUseClient);
 				}
diff --git a/src/Socket.cpp b/src/Socket.cpp
index 49185299..e339e261 100644
--- a/src/Socket.cpp
+++ b/src/Socket.cpp
@@ -175,7 +175,7 @@ void CSockManager::CDNSJob::runThread() {
 		hints.ai_socktype = SOCK_STREAM;
 		hints.ai_protocol = IPPROTO_TCP;
 		hints.ai_flags = AI_ADDRCONFIG;
-		iRes = getaddrinfo(sHostname.c_str(), NULL, &hints, &aiResult);
+		iRes = getaddrinfo(sHostname.c_str(), nullptr, &hints, &aiResult);
 		if (EAGAIN != iRes) {
 			break;
 		}
@@ -195,7 +195,7 @@ void CSockManager::CDNSJob::runMain() {
 		if (this->aiResult) {
 			DEBUG("And aiResult is not NULL...");
 		}
-		this->aiResult = NULL; // just for case. Maybe to call freeaddrinfo()?
+		this->aiResult = nullptr; // just for case. Maybe to call freeaddrinfo()?
 	}
 	pManager->SetTDNSThreadFinished(this->task, this->bBind, this->aiResult);
 }
@@ -207,7 +207,7 @@ void CSockManager::StartTDNSThread(TDNSTask* task, bool bBind) {
 	arg->task      = task;
 	arg->bBind     = bBind;
 	arg->iRes      = 0;
-	arg->aiResult  = NULL;
+	arg->aiResult  = nullptr;
 	arg->pManager  = this;
 
 	CThreadPool::Get().addJob(arg);
@@ -256,7 +256,7 @@ void CSockManager::SetTDNSThreadFinished(TDNSTask* task, bool bBind, addrinfo* a
 	SCString ssTargets6;
 	for (addrinfo* ai = task->aiTarget; ai; ai = ai->ai_next) {
 		char s[INET6_ADDRSTRLEN] = {};
-		getnameinfo(ai->ai_addr, ai->ai_addrlen, s, sizeof(s), NULL, 0, NI_NUMERICHOST);
+		getnameinfo(ai->ai_addr, ai->ai_addrlen, s, sizeof(s), nullptr, 0, NI_NUMERICHOST);
 		switch (ai->ai_family) {
 			case AF_INET:
 				ssTargets4.insert(s);
@@ -272,7 +272,7 @@ void CSockManager::SetTDNSThreadFinished(TDNSTask* task, bool bBind, addrinfo* a
 	SCString ssBinds6;
 	for (addrinfo* ai = task->aiBind; ai; ai = ai->ai_next) {
 		char s[INET6_ADDRSTRLEN] = {};
-		getnameinfo(ai->ai_addr, ai->ai_addrlen, s, sizeof(s), NULL, 0, NI_NUMERICHOST);
+		getnameinfo(ai->ai_addr, ai->ai_addrlen, s, sizeof(s), nullptr, 0, NI_NUMERICHOST);
 		switch (ai->ai_family) {
 			case AF_INET:
 				ssBinds4.insert(s);
@@ -361,8 +361,8 @@ void CSockManager::Connect(const CString& sHostname, u_short iPort, const CStrin
 	task->bSSL        = bSSL;
 	task->sBindhost   = sBindHost;
 	task->pcSock      = pcSock;
-	task->aiTarget    = NULL;
-	task->aiBind      = NULL;
+	task->aiTarget    = nullptr;
+	task->aiBind      = nullptr;
 	task->bDoneTarget = false;
 	if (sBindHost.empty()) {
 		task->bDoneBind = true;
@@ -411,7 +411,7 @@ CSocket::CSocket(CModule* pModule, const CString& sHostname, unsigned short uPor
 }
 
 CSocket::~CSocket() {
-	CUser *pUser = NULL;
+	CUser *pUser = nullptr;
 
 	// CWebSock could cause us to have a NULL pointer here
 	if (m_pModule) {
diff --git a/src/Template.cpp b/src/Template.cpp
index 0c26cf91..37c088ab 100644
--- a/src/Template.cpp
+++ b/src/Template.cpp
@@ -48,7 +48,7 @@ CTemplate* CTemplateLoopContext::GetRow(unsigned int uIndex) {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 CString CTemplateLoopContext::GetValue(const CString& sName, bool bFromIf) {
@@ -104,7 +104,7 @@ void CTemplate::Init() {
 	*/
 
 	ClearPaths();
-	m_pParent = NULL;
+	m_pParent = nullptr;
 }
 
 CString CTemplate::ExpandFile(const CString& sFilename, bool bFromInc) {
@@ -241,7 +241,7 @@ CTemplate* CTemplate::GetRow(const CString& sName, unsigned int uIndex) {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 vector<CTemplate*>* CTemplate::GetLoop(const CString& sName) {
@@ -261,7 +261,7 @@ vector<CTemplate*>* CTemplate::GetLoop(const CString& sName) {
 		return &(it->second);
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 bool CTemplate::PrintString(CString& sRet) {
@@ -456,7 +456,7 @@ bool CTemplate::Print(const CString& sFileName, ostream& oOut) {
 							bool bSort = (sArgs.Token(1).Left(4).Equals("SORT"));
 							vector<CTemplate*>* pvLoop = GetLoop(sLoopName);
 
-							if (bSort && pvLoop != NULL &&  pvLoop->size() > 1) {
+							if (bSort && pvLoop != nullptr &&  pvLoop->size() > 1) {
 								CString sKey;
 
 								if(sArgs.Token(1).TrimPrefix_n("SORT").Left(4).Equals("ASC=")) {
@@ -652,7 +652,7 @@ CTemplateLoopContext* CTemplate::GetCurLoopContext() {
 		return m_vLoopContexts.back();
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 bool CTemplate::ValidIf(const CString& sArgs) {
@@ -749,7 +749,7 @@ bool CTemplate::IsTrue(const CString& sName) {
 }
 
 bool CTemplate::HasLoop(const CString& sName) {
-	return (GetLoop(sName) != NULL);
+	return (GetLoop(sName) != nullptr);
 }
 
 CTemplate* CTemplate::GetParent(bool bRoot) {
diff --git a/src/Threads.cpp b/src/Threads.cpp
index c6d28a9e..84972d30 100644
--- a/src/Threads.cpp
+++ b/src/Threads.cpp
@@ -68,7 +68,7 @@ void CThreadPool::handlePipeReadable() const {
 }
 
 CJob *CThreadPool::getJobFromPipe() const {
-	CJob* a = NULL;
+	CJob* a = nullptr;
 	ssize_t need = sizeof(a);
 	ssize_t r = read(m_iJobPipe[0], &a, need);
 	if (r != need) {
diff --git a/src/User.cpp b/src/User.cpp
index 970039df..f8b7dc9d 100644
--- a/src/User.cpp
+++ b/src/User.cpp
@@ -100,7 +100,7 @@ CUser::~CUser() {
 
 	// Delete modules (unloads all modules!)
 	delete m_pModules;
-	m_pModules = NULL;
+	m_pModules = nullptr;
 
 	CZNC::Get().GetManager().DelCronByAddr(m_pUserTimer);
 
@@ -188,7 +188,7 @@ bool CUser::ParseConfig(CConfig* pConfig, CString& sError) {
 		if (sValue.ToBool()) {
 			CUtils::PrintAction("Loading Module [bouncedcc]");
 			CString sModRet;
-			bool bModRet = GetModules().LoadModule("bouncedcc", "", CModInfo::UserModule, this, NULL, sModRet);
+			bool bModRet = GetModules().LoadModule("bouncedcc", "", CModInfo::UserModule, this, nullptr, sModRet);
 
 			CUtils::PrintStatus(bModRet, sModRet);
 			if (!bModRet) {
@@ -449,20 +449,20 @@ bool CUser::ParseConfig(CConfig* pConfig, CString& sError) {
 CIRCNetwork* CUser::AddNetwork(const CString &sNetwork, CString& sErrorRet) {
 	if (!CIRCNetwork::IsValidNetwork(sNetwork)) {
 		sErrorRet = "Invalid network name. It should be alphanumeric. Not to be confused with server name";
-		return NULL;
+		return nullptr;
 	} else if (FindNetwork(sNetwork)) {
 		sErrorRet = "Network [" + sNetwork.Token(0) + "] already exists";
-		return NULL;
+		return nullptr;
 	}
 
 	CIRCNetwork* pNetwork = new CIRCNetwork(this, sNetwork);
 
 	bool bCancel = false;
-	USERMODULECALL(OnAddNetwork(*pNetwork, sErrorRet), this, NULL, &bCancel);
+	USERMODULECALL(OnAddNetwork(*pNetwork, sErrorRet), this, nullptr, &bCancel);
 	if(bCancel) {
 		RemoveNetwork(pNetwork);
 		delete pNetwork;
-		return NULL;
+		return nullptr;
 	}
 
 	return pNetwork;
@@ -492,7 +492,7 @@ bool CUser::DeleteNetwork(const CString& sNetwork) {
 
 	if (pNetwork) {
 		bool bCancel = false;
-		USERMODULECALL(OnDeleteNetwork(*pNetwork), this, NULL, &bCancel);
+		USERMODULECALL(OnDeleteNetwork(*pNetwork), this, nullptr, &bCancel);
 		if (!bCancel) {
 			delete pNetwork;
 			return true;
@@ -510,7 +510,7 @@ CIRCNetwork* CUser::FindNetwork(const CString& sNetwork) const {
 		}
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 const vector<CIRCNetwork*>& CUser::GetNetworks() const {
@@ -523,7 +523,7 @@ CString CUser::ExpandString(const CString& sStr) const {
 }
 
 CString& CUser::ExpandString(const CString& sStr, CString& sRet) const {
-	CString sTime = CUtils::CTime(time(NULL), m_sTimezone);
+	CString sTime = CUtils::CTime(time(nullptr), m_sTimezone);
 
 	sRet = sStr;
 	sRet.Replace("%user%", GetUserName());
@@ -648,7 +648,7 @@ void CUser::CloneNetworks(const CUser& User) {
 			CClient *pClient = vClients.front();
 			// This line will remove pClient from vClients,
 			// because it's a reference to the internal Network's vector.
-			pClient->SetNetwork(NULL);
+			pClient->SetNetwork(nullptr);
 		}
 
 		DeleteNetwork(*it);
@@ -747,9 +747,9 @@ bool CUser::Clone(const CUser& User, CString& sErrorRet, bool bCloneNetworks) {
 		CModule* pCurMod = vCurMods.FindModule(pNewMod->GetModName());
 
 		if (!pCurMod) {
-			vCurMods.LoadModule(pNewMod->GetModName(), pNewMod->GetArgs(), CModInfo::UserModule, this, NULL, sModRet);
+			vCurMods.LoadModule(pNewMod->GetModName(), pNewMod->GetArgs(), CModInfo::UserModule, this, nullptr, sModRet);
 		} else if (pNewMod->GetArgs() != pCurMod->GetArgs()) {
-			vCurMods.ReloadModule(pNewMod->GetModName(), pNewMod->GetArgs(), this, NULL, sModRet);
+			vCurMods.ReloadModule(pNewMod->GetModName(), pNewMod->GetArgs(), this, nullptr, sModRet);
 		}
 	}
 
@@ -989,7 +989,7 @@ bool CUser::PutUser(const CString& sLine, CClient* pClient, CClient* pSkipClient
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CUser::PutAllUser(const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -1002,7 +1002,7 @@ bool CUser::PutAllUser(const CString& sLine, CClient* pClient, CClient* pSkipCli
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CUser::PutStatus(const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -1017,7 +1017,7 @@ bool CUser::PutStatus(const CString& sLine, CClient* pClient, CClient* pSkipClie
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CUser::PutStatusNotice(const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -1032,7 +1032,7 @@ bool CUser::PutStatusNotice(const CString& sLine, CClient* pClient, CClient* pSk
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CUser::PutModule(const CString& sModule, const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -1046,7 +1046,7 @@ bool CUser::PutModule(const CString& sModule, const CString& sLine, CClient* pCl
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 bool CUser::PutModNotice(const CString& sModule, const CString& sLine, CClient* pClient, CClient* pSkipClient) {
@@ -1060,7 +1060,7 @@ bool CUser::PutModNotice(const CString& sModule, const CString& sLine, CClient*
 		}
 	}
 
-	return (pClient == NULL);
+	return (pClient == nullptr);
 }
 
 CString CUser::MakeCleanUserName(const CString& sUserName) {
@@ -1116,7 +1116,7 @@ bool CUser::LoadModule(const CString& sModName, const CString& sArgs, const CStr
 			}
 		}
 	} else {
-		bModRet = GetModules().LoadModule(sModName, sArgs, CModInfo::UserModule, this, NULL, sModRet);
+		bModRet = GetModules().LoadModule(sModName, sArgs, CModInfo::UserModule, this, nullptr, sModRet);
 	}
 
 	if (!bModRet) {
diff --git a/src/Utils.cpp b/src/Utils.cpp
index 7bd4c99f..e7009c7b 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -270,7 +270,7 @@ bool CUtils::GetInput(const CString& sPrompt, CString& sRet, const CString& sDef
 	PrintPrompt(sPrompt + sExtra);
 	char szBuf[1024];
 	memset(szBuf, 0, 1024);
-	if (fgets(szBuf, 1024, stdin) == NULL) {
+	if (fgets(szBuf, 1024, stdin) == nullptr) {
 		// Reading failed (Error? EOF?)
 		PrintError("Error while reading from stdin. Exiting...");
 		exit(-1);
diff --git a/src/WebModules.cpp b/src/WebModules.cpp
index 1c1c5e93..96244afc 100644
--- a/src/WebModules.cpp
+++ b/src/WebModules.cpp
@@ -97,7 +97,7 @@ bool CZNCTagHandler::HandleTag(CTemplate& Tmpl, const CString& sName, const CStr
 }
 
 CWebSession::CWebSession(const CString& sId, const CString& sIP) : m_sId(sId), m_sIP(sIP) {
-	m_pUser = NULL;
+	m_pUser = nullptr;
 	Sessions.m_mIPSessions.insert(make_pair(sIP, this));
 	UpdateLastActive();
 }
@@ -174,7 +174,7 @@ void CWebAuth::RefusedLogin(const CString& sReason) {
 		std::shared_ptr<CWebSession> spSession = m_pWebSock->GetSession();
 
 		spSession->AddError("Invalid login!");
-		spSession->SetUser(NULL);
+		spSession->SetUser(nullptr);
 
 		m_pWebSock->SetLoggedIn(false);
 		m_pWebSock->UnPauseRead();
@@ -186,10 +186,10 @@ void CWebAuth::RefusedLogin(const CString& sReason) {
 
 void CWebAuth::Invalidate() {
 	CAuthBase::Invalidate();
-	m_pWebSock = NULL;
+	m_pWebSock = nullptr;
 }
 
-CWebSock::CWebSock(const CString& sURIPrefix) : CHTTPSock(NULL, sURIPrefix) {
+CWebSock::CWebSock(const CString& sURIPrefix) : CHTTPSock(nullptr, sURIPrefix) {
 	m_bPathsSet = false;
 
 	m_Template.AddTagHandler(std::make_shared<CZNCTagHandler>(*this));
@@ -325,7 +325,7 @@ void CWebSock::SetPaths(CModule* pModule, bool bIsTemplate) {
 void CWebSock::SetVars() {
 	m_Template["SessionUser"] = GetUser();
 	m_Template["SessionIP"] = GetRemoteIP();
-	m_Template["Tag"] = CZNC::GetTag(GetSession()->GetUser() != NULL, true);
+	m_Template["Tag"] = CZNC::GetTag(GetSession()->GetUser() != nullptr, true);
 	m_Template["Version"] = CZNC::GetVersion();
 	m_Template["SkinName"] = GetSkinName();
 	m_Template["_CSRF_Check"] = GetCSRFCheck();
@@ -622,7 +622,7 @@ CWebSock::EPageReqResult CWebSock::OnPageRequestInternal(const CString& sURI, CS
 	} else if (sURI == "/robots.txt") {
 		return PrintStaticFile("/pub/robots.txt", sPageRet);
 	} else if (sURI == "/logout") {
-		GetSession()->SetUser(NULL);
+		GetSession()->SetUser(nullptr);
 		SetLoggedIn(false);
 		Redirect("/");
 
@@ -694,7 +694,7 @@ CWebSock::EPageReqResult CWebSock::OnPageRequestInternal(const CString& sURI, CS
 			return PAGE_DONE;
 		}
 
-		CIRCNetwork *pNetwork = NULL;
+		CIRCNetwork *pNetwork = nullptr;
 		if (eModType == CModInfo::NetworkModule) {
 			CString sNetwork = m_sPath.Token(0, false, "/");
 			m_sPath = m_sPath.Token(1, true, "/");
@@ -716,7 +716,7 @@ CWebSock::EPageReqResult CWebSock::OnPageRequestInternal(const CString& sURI, CS
 
 		DEBUG("Path [" + m_sPath + "], Module [" + m_sModName + "], Page [" + m_sPage + "]");
 
-		CModule *pModule = NULL;
+		CModule *pModule = nullptr;
 
 		switch (eModType) {
 			case CModInfo::GlobalModule:
@@ -831,7 +831,7 @@ std::shared_ptr<CWebSession> CWebSock::GetSession() {
 	const CString sCookieSessionId = GetRequestCookie("SessionId");
 	std::shared_ptr<CWebSession> *pSession = Sessions.m_mspSessions.GetItem(sCookieSessionId);
 
-	if (pSession != NULL) {
+	if (pSession != nullptr) {
 		// Refresh the timeout
 		Sessions.m_mspSessions.AddItem((*pSession)->GetId(), *pSession);
 		(*pSession)->UpdateLastActive();
@@ -853,7 +853,7 @@ std::shared_ptr<CWebSession> CWebSock::GetSession() {
 		sSessionID = CString::RandomString(32);
 		sSessionID += ":" + GetRemoteIP() + ":" + CString(GetRemotePort());
 		sSessionID += ":" + GetLocalIP()  + ":" + CString(GetLocalPort());
-		sSessionID += ":" + CString(time(NULL));
+		sSessionID += ":" + CString(time(nullptr));
 		sSessionID = sSessionID.SHA256();
 
 		DEBUG("Auto generated session: [" + sSessionID + "]");
@@ -889,7 +889,7 @@ Csock* CWebSock::GetSockObj(const CString& sHost, unsigned short uPort) {
 	// All listening is done by CListener, thus CWebSock should never have
 	// to listen, but since GetSockObj() is pure virtual...
 	DEBUG("CWebSock::GetSockObj() called - this should never happen!");
-	return NULL;
+	return nullptr;
 }
 
 CString CWebSock::GetSkinName() {
diff --git a/src/ZNCDebug.cpp b/src/ZNCDebug.cpp
index a6e1d253..6e36b577 100644
--- a/src/ZNCDebug.cpp
+++ b/src/ZNCDebug.cpp
@@ -29,7 +29,7 @@ bool CDebug::debug =
 
 CDebugStream::~CDebugStream() {
 	timeval tTime;
-	gettimeofday(&tTime, NULL);
+	gettimeofday(&tTime, nullptr);
 	time_t tSec = (time_t)tTime.tv_sec; // some systems (e.g. openbsd) define tv_sec as long int instead of time_t
 	tm tM;
 	tzset();// localtime_r requires this
diff --git a/src/ZNCString.cpp b/src/ZNCString.cpp
index abf1b473..9e9cca70 100644
--- a/src/ZNCString.cpp
+++ b/src/ZNCString.cpp
@@ -62,7 +62,7 @@ unsigned char* CString::strnchr(const unsigned char* src, unsigned char c, unsig
 		*piCount = 0;
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 int CString::CaseCmp(const CString& s, CString::size_type uLen) const {
@@ -104,7 +104,7 @@ bool CString::WildCmp(const CString& sWild, const CString& sString, CaseSensitiv
 
 	// Written by Jack Handy - jakkhandy@hotmail.com
 	const char *wild = sWld.c_str(), *CString = sStr.c_str();
-	const char *cp = NULL, *mp = NULL;
+	const char *cp = nullptr, *mp = nullptr;
 
 	while ((*CString) && (*wild != '*')) {
 		if ((*wild != *CString) && (*wild != '?')) {
@@ -222,7 +222,7 @@ CString CString::Escape_n(EEscape eFrom, EEscape eTo) const {
 							base = 16;
 						}
 
-						char* endptr = NULL;
+						char* endptr = nullptr;
 						unsigned long int b = strtol((const char*) (pTmp +2 + (base == 16)), &endptr, base);
 
 						if ((*endptr == ';') && (b <= 255)) { // incase they do something like &#7777777777;
@@ -1105,15 +1105,15 @@ bool CString::ToBool() const {
 			!sTrimmed.Equals("n"));
 }
 
-short CString::ToShort() const { return (short int)strtol(this->c_str(), (char**) NULL, 10); }
-unsigned short CString::ToUShort() const { return (unsigned short int)strtoul(this->c_str(), (char**) NULL, 10); }
-unsigned int CString::ToUInt() const { return (unsigned int)strtoul(this->c_str(), (char**) NULL, 10); }
-int CString::ToInt() const { return (int)strtol(this->c_str(), (char**) NULL, 10); }
-long CString::ToLong() const { return strtol(this->c_str(), (char**) NULL, 10); }
-unsigned long CString::ToULong() const { return strtoul(c_str(), NULL, 10); }
-unsigned long long CString::ToULongLong() const { return strtoull(c_str(), NULL, 10); }
-long long CString::ToLongLong() const { return strtoll(c_str(), NULL, 10); }
-double CString::ToDouble() const { return strtod(c_str(), NULL); }
+short CString::ToShort() const { return (short int)strtol(this->c_str(), (char**) nullptr, 10); }
+unsigned short CString::ToUShort() const { return (unsigned short int)strtoul(this->c_str(), (char**) nullptr, 10); }
+unsigned int CString::ToUInt() const { return (unsigned int)strtoul(this->c_str(), (char**) nullptr, 10); }
+int CString::ToInt() const { return (int)strtol(this->c_str(), (char**) nullptr, 10); }
+long CString::ToLong() const { return strtol(this->c_str(), (char**) nullptr, 10); }
+unsigned long CString::ToULong() const { return strtoul(c_str(), nullptr, 10); }
+unsigned long long CString::ToULongLong() const { return strtoull(c_str(), nullptr, 10); }
+long long CString::ToLongLong() const { return strtoll(c_str(), nullptr, 10); }
+double CString::ToDouble() const { return strtod(c_str(), nullptr); }
 
 
 bool CString::Trim(const CString& s) {
diff --git a/src/main.cpp b/src/main.cpp
index 1ab54df2..b4ac6e12 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -99,17 +99,17 @@ static inline int getopt_long(int argc, char * const argv[], const char *optstri
 #endif
 
 static const struct option g_LongOpts[] = {
-	{ "help",        no_argument,       0, 'h' },
-	{ "version",     no_argument,       0, 'v' },
-	{ "debug",       no_argument,       0, 'D' },
-	{ "foreground",  no_argument,       0, 'f' },
-	{ "no-color",    no_argument,       0, 'n' },
-	{ "allow-root",  no_argument,       0, 'r' },
-	{ "makeconf",    no_argument,       0, 'c' },
-	{ "makepass",    no_argument,       0, 's' },
-	{ "makepem",     no_argument,       0, 'p' },
-	{ "datadir",     required_argument, 0, 'd' },
-	{ 0, 0, 0, 0 }
+	{ "help",        no_argument,       nullptr, 'h' },
+	{ "version",     no_argument,       nullptr, 'v' },
+	{ "debug",       no_argument,       nullptr, 'D' },
+	{ "foreground",  no_argument,       nullptr, 'f' },
+	{ "no-color",    no_argument,       nullptr, 'n' },
+	{ "allow-root",  no_argument,       nullptr, 'r' },
+	{ "makeconf",    no_argument,       nullptr, 'c' },
+	{ "makepass",    no_argument,       nullptr, 's' },
+	{ "makepem",     no_argument,       nullptr, 'p' },
+	{ "datadir",     required_argument, nullptr, 'd' },
+	{ nullptr, 0, nullptr, 0 }
 };
 
 static void GenerateHelp(const char *appname) {
@@ -164,14 +164,14 @@ static void seedPRNG() {
 
 	// Try to find a seed which can't be as easily guessed as only time()
 
-	if (gettimeofday(&tv, NULL) == 0) {
+	if (gettimeofday(&tv, nullptr) == 0) {
 		seed = (unsigned int)tv.tv_sec;
 
 		// This is in [0:1e6], which means that roughly 20 bits are
 		// actually used, let's try to shuffle the high bits.
 		seed ^= uint32_t((tv.tv_usec << 10) | tv.tv_usec);
 	} else
-		seed = (unsigned int)time(NULL);
+		seed = (unsigned int)time(nullptr);
 
 	seed ^= rand();
 	seed ^= getpid();
@@ -393,19 +393,19 @@ int main(int argc, char** argv) {
 	sigemptyset(&sa.sa_mask);
 
 	sa.sa_handler = SIG_IGN;
-	sigaction(SIGPIPE, &sa, (struct sigaction*) NULL);
+	sigaction(SIGPIPE, &sa, (struct sigaction*) nullptr);
 
 	sa.sa_handler = signalHandler;
-	sigaction(SIGHUP,  &sa, (struct sigaction*) NULL);
-	sigaction(SIGUSR1, &sa, (struct sigaction*) NULL);
+	sigaction(SIGHUP,  &sa, (struct sigaction*) nullptr);
+	sigaction(SIGUSR1, &sa, (struct sigaction*) nullptr);
 
 	// Once this signal is caught, the signal handler is reset
 	// to SIG_DFL. This avoids endless loop with signals.
 	sa.sa_flags = SA_RESETHAND;
 	sa.sa_handler = die;
-	sigaction(SIGINT,  &sa, (struct sigaction*) NULL);
-	sigaction(SIGQUIT, &sa, (struct sigaction*) NULL);
-	sigaction(SIGTERM, &sa, (struct sigaction*) NULL);
+	sigaction(SIGINT,  &sa, (struct sigaction*) nullptr);
+	sigaction(SIGQUIT, &sa, (struct sigaction*) nullptr);
+	sigaction(SIGTERM, &sa, (struct sigaction*) nullptr);
 
 	int iRet = 0;
 
@@ -422,10 +422,10 @@ int main(int argc, char** argv) {
 					strdup(argv[0]),
 					strdup("--datadir"),
 					strdup(pZNC->GetZNCPath().c_str()),
-					NULL,
-					NULL,
-					NULL,
-					NULL
+					nullptr,
+					nullptr,
+					nullptr,
+					nullptr
 				};
 				int pos = 3;
 				if (CDebug::Debug())
diff --git a/src/znc.cpp b/src/znc.cpp
index 7ebde5f9..818e636e 100644
--- a/src/znc.cpp
+++ b/src/znc.cpp
@@ -48,12 +48,12 @@ CZNC::CZNC() {
 	m_uBytesRead = 0;
 	m_uBytesWritten = 0;
 	m_uiMaxBufferSize = 500;
-	m_pConnectQueueTimer = NULL;
+	m_pConnectQueueTimer = nullptr;
 	m_uiConnectPaused = 0;
 	m_eConfigState = ECONFIG_NOTHING;
-	m_TimeStarted = time(NULL);
+	m_TimeStarted = time(nullptr);
 	m_sConnectThrottle.SetTTL(30000);
-	m_pLockFile = NULL;
+	m_pLockFile = nullptr;
 	m_bProtectWebSessions = true;
 	m_bHideVersion = false;
 	m_uDisabledSSLProtocols = Csock::EDP_SSL;
@@ -80,7 +80,7 @@ CZNC::~CZNC() {
 		a->second->SetBeingDeleted(true);
 	}
 
-	m_pConnectQueueTimer = NULL;
+	m_pConnectQueueTimer = nullptr;
 	// This deletes m_pConnectQueueTimer
 	m_Manager.Cleanup();
 	DeleteUsers();
@@ -141,7 +141,7 @@ CString CZNC::GetCompileOptionsString() {
 }
 
 CString CZNC::GetUptime() const {
-	time_t now = time(NULL);
+	time_t now = time(nullptr);
 	return CString::ToTimeStr(now - TimeStarted());
 }
 
@@ -235,12 +235,12 @@ CFile* CZNC::InitPidFile() {
 		return new CFile(sFile);
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 bool CZNC::WritePidFile(int iPid) {
 	CFile* File = InitPidFile();
-	if (File == NULL)
+	if (File == nullptr)
 		return false;
 
 	CUtils::PrintAction("Writing pid file [" + File->GetLongName() + "]");
@@ -259,7 +259,7 @@ bool CZNC::WritePidFile(int iPid) {
 
 bool CZNC::DeletePidFile() {
 	CFile* File = InitPidFile();
-	if (File == NULL)
+	if (File == nullptr)
 		return false;
 
 	CUtils::PrintAction("Deleting pid file [" + File->GetLongName() + "]");
@@ -1015,7 +1015,7 @@ bool CZNC::DoRehash(CString& sError)
 		if (!pOldMod) {
 			CUtils::PrintAction("Loading global module [" + sModName + "]");
 
-			bool bModRet = GetModules().LoadModule(sModName, sArgs, CModInfo::GlobalModule, NULL, NULL, sModRet);
+			bool bModRet = GetModules().LoadModule(sModName, sArgs, CModInfo::GlobalModule, nullptr, nullptr, sModRet);
 
 			CUtils::PrintStatus(bModRet, sModRet);
 			if (!bModRet) {
@@ -1025,7 +1025,7 @@ bool CZNC::DoRehash(CString& sError)
 		} else if (pOldMod->GetArgs() != sArgs) {
 			CUtils::PrintAction("Reloading global module [" + sModName + "]");
 
-			bool bModRet = GetModules().ReloadModule(sModName, sArgs, NULL, NULL, sModRet);
+			bool bModRet = GetModules().ReloadModule(sModName, sArgs, nullptr, nullptr, sModRet);
 
 			CUtils::PrintStatus(bModRet, sModRet);
 			if (!bModRet) {
@@ -1047,7 +1047,7 @@ bool CZNC::DoRehash(CString& sError)
 			CUtils::PrintAction("Loading global Module [identfile]");
 
 			CString sModRet;
-			bool bModRet = GetModules().LoadModule("identfile", "", CModInfo::GlobalModule, NULL, NULL, sModRet);
+			bool bModRet = GetModules().LoadModule("identfile", "", CModInfo::GlobalModule, nullptr, nullptr, sModRet);
 
 			CUtils::PrintStatus(bModRet, sModRet);
 			if (!bModRet) {
@@ -1184,7 +1184,7 @@ bool CZNC::DoRehash(CString& sError)
 	for (subIt = subConf.begin(); subIt != subConf.end(); ++subIt) {
 		const CString& sUserName = subIt->first;
 		CConfig* pSubConf = subIt->second.m_pSubConfig;
-		CUser* pRealUser = NULL;
+		CUser* pRealUser = nullptr;
 
 		CUtils::PrintMessage("Loading user [" + sUserName + "]");
 
@@ -1209,7 +1209,7 @@ bool CZNC::DoRehash(CString& sError)
 		if (!pUser->ParseConfig(pSubConf, sError)) {
 			CUtils::PrintError(sError);
 			delete pUser;
-			pUser = NULL;
+			pUser = nullptr;
 			return false;
 		}
 
@@ -1230,7 +1230,7 @@ bool CZNC::DoRehash(CString& sError)
 			}
 			pUser->SetBeingDeleted(true);
 			delete pUser;
-			pUser = NULL;
+			pUser = nullptr;
 		} else if (!AddUser(pUser, sErr)) {
 			sError = "Invalid user [" + pUser->GetUserName() + "] " + sErr;
 		}
@@ -1240,13 +1240,13 @@ bool CZNC::DoRehash(CString& sError)
 			if (pUser) {
 				pUser->SetBeingDeleted(true);
 				delete pUser;
-				pUser = NULL;
+				pUser = nullptr;
 			}
 			return false;
 		}
 
-		pUser = NULL;
-		pRealUser = NULL;
+		pUser = nullptr;
+		pRealUser = nullptr;
 	}
 
 	if (!config.empty()) {
@@ -1385,10 +1385,10 @@ void CZNC::Broadcast(const CString& sMessage, bool bAdminOnly,
 			CString sMsg = sMessage;
 
 			bool bContinue = false;
-			USERMODULECALL(OnBroadcast(sMsg), a->second, NULL, &bContinue);
+			USERMODULECALL(OnBroadcast(sMsg), a->second, nullptr, &bContinue);
 			if (bContinue) continue;
 
-			a->second->PutStatusNotice("*** " + sMsg, NULL, pSkipClient);
+			a->second->PutStatusNotice("*** " + sMsg, nullptr, pSkipClient);
 		}
 	}
 }
@@ -1400,7 +1400,7 @@ CModule* CZNC::FindModule(const CString& sModName, const CString& sUsername) {
 
 	CUser* pUser = FindUser(sUsername);
 
-	return (!pUser) ? NULL : pUser->GetModules().FindModule(sModName);
+	return (!pUser) ? nullptr : pUser->GetModules().FindModule(sModName);
 }
 
 CModule* CZNC::FindModule(const CString& sModName, CUser* pUser) {
@@ -1461,7 +1461,7 @@ bool CZNC::UpdateModule(const CString &sModule) {
 
 	// Reload the global module
 	if (bGlobal) {
-		if (!GetModules().LoadModule(sModule, sGlobalArgs, CModInfo::GlobalModule, NULL, NULL, sErr)) {
+		if (!GetModules().LoadModule(sModule, sGlobalArgs, CModInfo::GlobalModule, nullptr, nullptr, sErr)) {
 			DEBUG("Failed to reload [" <<  sModule << "] globally [" << sErr << "]");
 			bError = true;
 		}
@@ -1472,7 +1472,7 @@ bool CZNC::UpdateModule(const CString &sModule) {
 		CUser *pUser = musIt->first;
 		CString& sArgs = musIt->second;
 
-		if (!pUser->GetModules().LoadModule(sModule, sArgs, CModInfo::UserModule, pUser, NULL, sErr)) {
+		if (!pUser->GetModules().LoadModule(sModule, sArgs, CModInfo::UserModule, pUser, nullptr, sErr)) {
 			DEBUG("Failed to reload [" <<  sModule << "] for ["
 					<< pUser->GetUserName() << "] [" << sErr << "]");
 			bError = true;
@@ -1502,7 +1502,7 @@ CUser* CZNC::FindUser(const CString& sUsername) {
 		return it->second;
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 bool CZNC::DeleteUser(const CString& sUsername) {
@@ -1517,7 +1517,7 @@ bool CZNC::DeleteUser(const CString& sUsername) {
 }
 
 bool CZNC::AddUser(CUser* pUser, CString& sErrorRet) {
-	if (FindUser(pUser->GetUserName()) != NULL) {
+	if (FindUser(pUser->GetUserName()) != nullptr) {
 		sErrorRet = "User already exists";
 		DEBUG("User [" << pUser->GetUserName() << "] - already exists");
 		return false;
@@ -1550,7 +1550,7 @@ CListener* CZNC::FindListener(u_short uPort, const CString& sBindHost, EAddrType
 			continue;
 		return *it;
 	}
-	return NULL;
+	return nullptr;
 }
 
 bool CZNC::AddListener(const CString& sLine, CString& sError) {
@@ -1769,7 +1769,7 @@ bool CZNC::DelListener(CListener* pListener) {
 	return false;
 }
 
-static CZNC* s_pZNC = NULL;
+static CZNC* s_pZNC = nullptr;
 
 void CZNC::CreateInstance() {
 	if (s_pZNC)
@@ -1784,7 +1784,7 @@ CZNC& CZNC::Get() {
 
 void CZNC::DestroyInstance() {
 	delete s_pZNC;
-	s_pZNC = NULL;
+	s_pZNC = nullptr;
 }
 
 CZNC::TrafficStatsMap CZNC::GetTrafficStats(TrafficStatsPair &Users,
@@ -1804,7 +1804,7 @@ CZNC::TrafficStatsMap CZNC::GetTrafficStats(TrafficStatsPair &Users,
 	}
 
 	for (CSockManager::const_iterator it = m_Manager.begin(); it != m_Manager.end(); ++it) {
-		CUser *pUser = NULL;
+		CUser *pUser = nullptr;
 		if ((*it)->GetSockName().Left(5) == "IRC::") {
 			pUser = ((CIRCSock *) *it)->GetNetwork()->GetUser();
 		} else if ((*it)->GetSockName().Left(5) == "USR::") {
@@ -1913,7 +1913,7 @@ void CZNC::SetConnectDelay(unsigned int i) {
 		// Don't hammer server with our failed connects
 		i = 1;
 	}
-	if (m_uiConnectDelay != i && m_pConnectQueueTimer != NULL) {
+	if (m_uiConnectDelay != i && m_pConnectQueueTimer != nullptr) {
 		m_pConnectQueueTimer->Start(i);
 	}
 	m_uiConnectDelay = i;
@@ -1930,7 +1930,7 @@ void CZNC::DisableConnectQueue() {
 	if (m_pConnectQueueTimer) {
 		// This will kill the cron
 		m_pConnectQueueTimer->Stop();
-		m_pConnectQueueTimer = NULL;
+		m_pConnectQueueTimer = nullptr;
 	}
 }
 
@@ -1967,7 +1967,7 @@ void CZNC::AddNetworkToQueue(CIRCNetwork *pNetwork) {
 
 void CZNC::LeakConnectQueueTimer(CConnectQueueTimer *pTimer) {
 	if (m_pConnectQueueTimer == pTimer)
-		m_pConnectQueueTimer = NULL;
+		m_pConnectQueueTimer = nullptr;
 }
 
 bool CZNC::WaitForChildLock() {