diff --git a/include/znc/Modules.h b/include/znc/Modules.h
index 6f1531c3..f6ab6dd9 100644
--- a/include/znc/Modules.h
+++ b/include/znc/Modules.h
@@ -509,7 +509,7 @@ public:
 	virtual EModRet OnBroadcast(CString& sMessage);
 
 	/** This module hook is called when a user mode on a channel changes.
-	 *  @param pOpNick The nick who sent the mode change, or NULL if set by server.
+	 *  @param pOpNick The nick who sent the mode change, or nullptr if set by server.
 	 *  @param Nick The nick whose channel mode changes.
 	 *  @param Channel The channel on which the user mode is changed.
 	 *  @param uMode The mode character that is changed, e.g. '@' for op.
@@ -534,7 +534,7 @@ public:
 	virtual void OnDevoice2(const CNick* pOpNick, const CNick& Nick, CChan& Channel, bool bNoChange);
 	virtual void OnDevoice(const CNick& OpNick, const CNick& Nick, CChan& Channel, bool bNoChange);
 	/** Called on an individual channel mode change.
-	 *  @param pOpNick The nick who changes the channel mode, or NULL if set by server.
+	 *  @param pOpNick The nick who changes the channel mode, or nullptr if set by server.
 	 *  @param Channel The channel whose mode is changed.
 	 *  @param uMode The mode character that is changed.
 	 *  @param sArg The argument to the mode character, if any.
@@ -545,7 +545,7 @@ public:
 	virtual void OnMode(const CNick& OpNick, CChan& Channel, char uMode, const CString& sArg, bool bAdded, bool bNoChange);
 	/** Called on any channel mode change. This is called before the more
 	 *  detailed mode hooks like e.g. OnOp() and OnMode().
-	 *  @param pOpNick The nick who changes the channel mode, or NULL if set by server.
+	 *  @param pOpNick The nick who changes the channel mode, or nullptr if set by server.
 	 *  @param Channel The channel whose mode is changed.
 	 *  @param sModes The raw mode change, e.g. "+s-io".
 	 *  @param sArgs All arguments to the mode change from sModes.
@@ -953,7 +953,7 @@ public:
 	bool AddCommand(const CString& sCmd, const CString& sArgs, const CString& sDesc, std::function<void(const CString& sLine)> func);
 	/// @return True if the command was successfully removed.
 	bool RemCommand(const CString& sCmd);
-	/// @return The CModCommand instance or NULL if none was found.
+	/// @return The CModCommand instance or nullptr if none was found.
 	const CModCommand* FindCommand(const CString& sCmd) const;
 	/** This function tries to dispatch the given command via the correct
 	 * instance of CModCommand. Before this can be called, commands have to
@@ -999,12 +999,12 @@ public:
 	const CString& GetModPath() const { return m_sModPath; }
 
 	/** @returns For user modules this returns the user for which this
-	 *           module was loaded. For global modules this returns NULL,
+	 *           module was loaded. For global modules this returns nullptr,
 	 *           except when we are in a user-specific module hook in which
 	 *           case this is the user pointer.
 	 */
 	CUser* GetUser() const { return m_pUser; }
-	/** @returns NULL except when we are in a client-specific module hook in
+	/** @returns nullptr except when we are in a client-specific module hook in
 	 *           which case this is the client for which the hook is called.
 	 */
 	CIRCNetwork* GetNetwork() const { return m_pNetwork; }
diff --git a/include/znc/Utils.h b/include/znc/Utils.h
index b1a314ed..5333d4e3 100644
--- a/include/znc/Utils.h
+++ b/include/znc/Utils.h
@@ -310,9 +310,9 @@ public:
 	}
 
 	/**
-	 * @brief Performs a Cleanup() and returns a pointer to the object, or NULL
+	 * @brief Performs a Cleanup() and returns a pointer to the object, or nullptr
 	 * @param Item The item to check for
-	 * @return Pointer to the item or NULL if there is no suitable one
+	 * @return Pointer to the item or nullptr if there is no suitable one
 	 */
 	V* GetItem(const K& Item) {
 		Cleanup();
diff --git a/include/znc/main.h b/include/znc/main.h
index 254937e3..db173d5e 100644
--- a/include/znc/main.h
+++ b/include/znc/main.h
@@ -107,7 +107,7 @@ extern bool ZNC_NO_NEED_TO_DO_ANYTHING_ON_MODULE_CALL_EXITER;
 			*macEXITER = true;                 \
 			break;                                                \
 		}                                                            \
-		if (macNETWORK != NULL) {                                      \
+		if (macNETWORK != nullptr) {                                      \
 			CModules& NMods = macNETWORK->GetModules();            \
 			CClient* pOldNClient = NMods.GetClient();              \
 			NMods.SetClient(macCLIENT);                            \
@@ -120,10 +120,10 @@ extern bool ZNC_NO_NEED_TO_DO_ANYTHING_ON_MODULE_CALL_EXITER;
 	} while (false)
 
 #define GLOBALMODULECALL(macFUNC, macEXITER) \
-	_GLOBALMODULECALL(macFUNC, NULL, NULL, NULL, macEXITER)
+	_GLOBALMODULECALL(macFUNC, nullptr, nullptr, nullptr, macEXITER)
 
 #define USERMODULECALL(macFUNC, macUSER, macCLIENT, macEXITER) \
-	_USERMODULECALL(macFUNC, macUSER, NULL, macCLIENT, macEXITER)
+	_USERMODULECALL(macFUNC, macUSER, nullptr, macCLIENT, macEXITER)
 
 /** @mainpage
  *  Welcome to the API documentation for ZNC.
diff --git a/modules/alias.cpp b/modules/alias.cpp
index 149f3256..3777d83a 100644
--- a/modules/alias.cpp
+++ b/modules/alias.cpp
@@ -72,7 +72,7 @@ public:
 	}
 
 	// constructors
-	CAlias() : parent(NULL) {}
+	CAlias() : parent(nullptr) {}
 	CAlias(CModule *new_parent, const CString &new_name) : parent(new_parent) { SetName(new_name); }
 
 	// produce a command string from this alias' command list
@@ -330,7 +330,7 @@ public:
 		}
 		catch (std::exception &e)
 		{
-			CString my_nick = (GetNetwork() == NULL ? "" : GetNetwork()->GetCurNick());
+			CString my_nick = (GetNetwork() == nullptr ? "" : GetNetwork()->GetCurNick());
 			if (my_nick.empty()) my_nick = "*";
 			PutUser(CString(":znc.in 461 " + my_nick + " " + current_alias.GetName() + " :ZNC alias error: ") + e.what());
 			return HALTCORE;
diff --git a/modules/autoop.cpp b/modules/autoop.cpp
index 77e590d2..18421afc 100644
--- a/modules/autoop.cpp
+++ b/modules/autoop.cpp
@@ -401,7 +401,7 @@ public:
 	CAutoOpUser* FindUser(const CString& sUser) {
 		map<CString, CAutoOpUser*>::iterator it = m_msUsers.find(sUser.AsLower());
 
-		return (it != m_msUsers.end()) ? it->second : NULL;
+		return (it != m_msUsers.end()) ? it->second : nullptr;
 	}
 
 	CAutoOpUser* FindUserByHost(const CString& sHostmask, const CString& sChannel = "") {
@@ -413,7 +413,7 @@ public:
 			}
 		}
 
-		return NULL;
+		return nullptr;
 	}
 
 	bool CheckAutoOp(const CNick& Nick, CChan& Channel) {
@@ -452,7 +452,7 @@ public:
 	CAutoOpUser* AddUser(const CString& sUser, const CString& sKey, const CString& sHosts, const CString& sChans) {
 		if (m_msUsers.find(sUser) != m_msUsers.end()) {
 			PutModule("That user already exists");
-			return NULL;
+			return nullptr;
 		}
 
 		CAutoOpUser* pUser = new CAutoOpUser(sUser, sKey, sHosts, sChans);
@@ -465,7 +465,7 @@ public:
 		// Validate before responding - don't blindly trust everyone
 		bool bValid = false;
 		bool bMatchedHost = false;
-		CAutoOpUser* pUser = NULL;
+		CAutoOpUser* pUser = nullptr;
 
 		for (map<CString, CAutoOpUser*>::iterator it = m_msUsers.begin(); it != m_msUsers.end(); ++it) {
 			pUser = it->second;
diff --git a/modules/autovoice.cpp b/modules/autovoice.cpp
index c47cf61a..6e449bf1 100644
--- a/modules/autovoice.cpp
+++ b/modules/autovoice.cpp
@@ -267,7 +267,7 @@ public:
 	CAutoVoiceUser* FindUser(const CString& sUser) {
 		map<CString, CAutoVoiceUser*>::iterator it = m_msUsers.find(sUser.AsLower());
 
-		return (it != m_msUsers.end()) ? it->second : NULL;
+		return (it != m_msUsers.end()) ? it->second : nullptr;
 	}
 
 	CAutoVoiceUser* FindUserByHost(const CString& sHostmask, const CString& sChannel = "") {
@@ -279,7 +279,7 @@ public:
 			}
 		}
 
-		return NULL;
+		return nullptr;
 	}
 
 	void DelUser(const CString& sUser) {
@@ -298,7 +298,7 @@ public:
 	CAutoVoiceUser* AddUser(const CString& sUser, const CString& sHost, const CString& sChans) {
 		if (m_msUsers.find(sUser) != m_msUsers.end()) {
 			PutModule("That user already exists");
-			return NULL;
+			return nullptr;
 		}
 
 		CAutoVoiceUser* pUser = new CAutoVoiceUser(sUser, sHost, sChans);
diff --git a/modules/awaystore.cpp b/modules/awaystore.cpp
index 116d8fda..1a706641 100644
--- a/modules/awaystore.cpp
+++ b/modules/awaystore.cpp
@@ -355,7 +355,7 @@ public:
 			else if (!sReason.empty())
 				m_sReason = sReason;
 
-			time_t iTime = time(NULL);
+			time_t iTime = time(nullptr);
 			char *pTime = ctime(&iTime);
 			CString sTime;
 			if (pTime)
@@ -393,14 +393,14 @@ public:
 	EModRet OnPrivMsg(CNick& Nick, CString& sMessage) override
 	{
 		if (m_bIsAway)
-			AddMessage(time(NULL), Nick, sMessage);
+			AddMessage(time(nullptr), Nick, sMessage);
 		return(CONTINUE);
 	}
 
 	EModRet OnPrivAction(CNick& Nick, CString& sMessage) override
 	{
 		if (m_bIsAway) {
-			AddMessage(time(NULL), Nick, "* " + sMessage);
+			AddMessage(time(nullptr), Nick, "* " + sMessage);
 		}
 		return(CONTINUE);
 	}
@@ -433,7 +433,7 @@ public:
 	}
 
 	time_t GetTimeStamp() const { return(m_iLastSentData); }
-	void Ping() { m_iLastSentData = time(NULL); }
+	void Ping() { m_iLastSentData = time(nullptr); }
 	time_t GetAwayTime() { return m_iAutoAway; }
 	void SetAwayTime(time_t u) { m_iAutoAway = u; }
 
@@ -505,7 +505,7 @@ void CAwayJob::RunJob()
 
 	if (!p->IsAway())
 	{
-		time_t iNow = time(NULL);
+		time_t iNow = time(nullptr);
 
 		if ((iNow - p->GetTimeStamp()) > p->GetAwayTime() && p->GetAwayTime() != 0)
 			p->Away();
diff --git a/modules/bouncedcc.cpp b/modules/bouncedcc.cpp
index af21ee8b..c429b5fb 100644
--- a/modules/bouncedcc.cpp
+++ b/modules/bouncedcc.cpp
@@ -278,7 +278,7 @@ CDCCBounce::CDCCBounce(CBounceDCCMod* pMod, unsigned long uLongIP, unsigned shor
 	m_pModule = pMod;
 	m_bIsChat = bIsChat;
 	m_sLocalIP = pMod->GetLocalDCCIP();
-	m_pPeer = NULL;
+	m_pPeer = nullptr;
 	m_bIsRemote = false;
 
 	if (bIsChat) {
@@ -294,7 +294,7 @@ CDCCBounce::CDCCBounce(CBounceDCCMod* pMod, const CString& sHostname, unsigned s
 	m_uRemotePort = 0;
 	m_bIsChat = bIsChat;
 	m_pModule = pMod;
-	m_pPeer = NULL;
+	m_pPeer = nullptr;
 	m_sRemoteNick = sRemoteNick;
 	m_sFileName = sFileName;
 	m_sRemoteIP = sRemoteIP;
@@ -311,7 +311,7 @@ CDCCBounce::CDCCBounce(CBounceDCCMod* pMod, const CString& sHostname, unsigned s
 CDCCBounce::~CDCCBounce() {
 	if (m_pPeer) {
 		m_pPeer->Shutdown();
-		m_pPeer = NULL;
+		m_pPeer = nullptr;
 	}
 }
 
@@ -409,7 +409,7 @@ void CDCCBounce::Disconnected() {
 }
 
 void CDCCBounce::Shutdown() {
-	m_pPeer = NULL;
+	m_pPeer = nullptr;
 	DEBUG(GetSockName() << " == Close(); because my peer told me to");
 	Close();
 }
diff --git a/modules/certauth.cpp b/modules/certauth.cpp
index 6f017ec4..d4e46101 100644
--- a/modules/certauth.cpp
+++ b/modules/certauth.cpp
@@ -51,7 +51,7 @@ public:
 		for (MCString::const_iterator it1 = BeginNV(); it1 != EndNV(); ++it1) {
 			VCString vsKeys;
 
-			if (CZNC::Get().FindUser(it1->first) == NULL) {
+			if (CZNC::Get().FindUser(it1->first) == nullptr) {
 				DEBUG("Unknown user in saved data [" + it1->first + "]");
 				continue;
 			}
@@ -106,7 +106,7 @@ public:
 		Csock *pSock = Auth->GetSocket();
 		CUser *pUser = CZNC::Get().FindUser(sUser);
 
-		if (pSock == NULL || pUser == NULL)
+		if (pSock == nullptr || pUser == nullptr)
 			return CONTINUE;
 
 		const CString sPubKey = GetKey(pSock);
diff --git a/modules/clientnotify.cpp b/modules/clientnotify.cpp
index 40d96d34..d2cf2d34 100644
--- a/modules/clientnotify.cpp
+++ b/modules/clientnotify.cpp
@@ -35,10 +35,10 @@ protected:
 
 	void SendNotification(const CString& sMessage) {
 		if(m_sMethod == "message") {
-			GetUser()->PutStatus(sMessage, NULL, GetClient());
+			GetUser()->PutStatus(sMessage, nullptr, GetClient());
 		}
 		else if(m_sMethod == "notice") {
-			GetUser()->PutStatusNotice(sMessage, NULL, GetClient());
+			GetUser()->PutStatusNotice(sMessage, nullptr, GetClient());
 		}
 	}
 
diff --git a/modules/controlpanel.cpp b/modules/controlpanel.cpp
index 04ae64ca..c1aad504 100644
--- a/modules/controlpanel.cpp
+++ b/modules/controlpanel.cpp
@@ -149,11 +149,11 @@ class CAdminMod : public CModule {
 		CUser *pUser = CZNC::Get().FindUser(sUsername);
 		if (!pUser) {
 			PutModule("Error: User [" + sUsername + "] not found.");
-			return NULL;
+			return nullptr;
 		}
 		if (pUser != GetUser() && !GetUser()->IsAdmin()) {
 			PutModule("Error: You need to have admin rights to modify other users!");
-			return NULL;
+			return nullptr;
 		}
 		return pUser;
 	}
@@ -440,7 +440,7 @@ class CAdminMod : public CModule {
 		const CString sUsername = sLine.Token(2);
 		const CString sNetwork = sLine.Token(3);
 
-		CIRCNetwork *pNetwork = NULL;
+		CIRCNetwork *pNetwork = nullptr;
 
 		if (sUsername.empty()) {
 			pNetwork = CModule::GetNetwork();
@@ -497,8 +497,8 @@ class CAdminMod : public CModule {
 		const CString sNetwork = sLine.Token(3);
 		const CString sValue = sLine.Token(4, true);
 
-		CUser *pUser = NULL;
-		CIRCNetwork *pNetwork = NULL;
+		CUser *pUser = nullptr;
+		CIRCNetwork *pNetwork = nullptr;
 
 		if (sUsername.empty()) {
 			pUser = GetUser();
@@ -1285,7 +1285,7 @@ class CAdminMod : public CModule {
 		if (!pUser)
 			return;
 
-		LoadModuleFor(pUser->GetModules(), sModName, sArgs, CModInfo::UserModule, pUser, NULL);
+		LoadModuleFor(pUser->GetModules(), sModName, sArgs, CModInfo::UserModule, pUser, nullptr);
 	}
 
 	void LoadModuleForNetwork(const CString& sLine) {
diff --git a/modules/crypt.cpp b/modules/crypt.cpp
index bf7c0aef..67438d4f 100644
--- a/modules/crypt.cpp
+++ b/modules/crypt.cpp
@@ -69,7 +69,7 @@ public:
 			if (pChan) {
 				if (!pChan->AutoClearChanBuffer())
 					pChan->AddBuffer(":" + NickPrefix() + _NAMEDFMT(sNickMask) + " PRIVMSG " + _NAMEDFMT(sTarget) + " :{text}", sMessage);
-				GetUser()->PutUser(":" + NickPrefix() + sNickMask + " PRIVMSG " + sTarget + " :" + sMessage, NULL, GetClient());
+				GetUser()->PutUser(":" + NickPrefix() + sNickMask + " PRIVMSG " + sTarget + " :" + sMessage, nullptr, GetClient());
 			}
 
 			CString sMsg = MakeIvec() + sMessage;
diff --git a/modules/ctcpflood.cpp b/modules/ctcpflood.cpp
index e3111366..db43cde6 100644
--- a/modules/ctcpflood.cpp
+++ b/modules/ctcpflood.cpp
@@ -66,8 +66,8 @@ public:
 		if (sMessage.Token(0).Equals("ACTION"))
 			return CONTINUE;
 
-		if (m_tLastCTCP + m_iThresholdSecs < time(NULL)) {
-			m_tLastCTCP = time(NULL);
+		if (m_tLastCTCP + m_iThresholdSecs < time(nullptr)) {
+			m_tLastCTCP = time(nullptr);
 			m_iNumCTCP = 0;
 		}
 
@@ -79,7 +79,7 @@ public:
 			PutModule("Limit reached by [" + Nick.GetHostMask() + "], blocking all CTCP");
 
 		// Reset the timeout so that we continue blocking messages
-		m_tLastCTCP = time(NULL);
+		m_tLastCTCP = time(nullptr);
 
 		return HALT;
 	}
diff --git a/modules/cyrusauth.cpp b/modules/cyrusauth.cpp
index 6167bd51..6595fe5e 100644
--- a/modules/cyrusauth.cpp
+++ b/modules/cyrusauth.cpp
@@ -72,7 +72,7 @@ public:
 			return false;
 		}
 
-		if (sasl_server_init(NULL, NULL) != SASL_OK) {
+		if (sasl_server_init(nullptr, nullptr) != SASL_OK) {
 			sMessage = "SASL Could Not Be Initialized - Halting Startup";
 			return false;
 		}
@@ -81,8 +81,8 @@ public:
 		m_cbs[0].proc = reinterpret_cast<int(*)()>(CSASLAuthMod::getopt);
 		m_cbs[0].context = this;
 		m_cbs[1].id = SASL_CB_LIST_END;
-		m_cbs[1].proc = NULL;
-		m_cbs[1].context = NULL;
+		m_cbs[1].proc = nullptr;
+		m_cbs[1].context = nullptr;
 
 		return true;
 	}
@@ -91,7 +91,7 @@ public:
 		const CString& sUsername = Auth->GetUsername();
 		const CString& sPassword = Auth->GetPassword();
 		CUser *pUser(CZNC::Get().FindUser(sUsername));
-		sasl_conn_t *sasl_conn(NULL);
+		sasl_conn_t *sasl_conn(nullptr);
 		bool bSuccess = false;
 
 		if (!pUser && !CreateUser()) {
@@ -102,7 +102,7 @@ public:
 		if (m_Cache.HasItem(sCacheKey)) {
 			bSuccess = true;
 			DEBUG("saslauth: Found [" + sUsername + "] in cache");
-		} else if (sasl_server_new("znc", NULL, NULL, NULL, NULL, m_cbs, 0, &sasl_conn) == SASL_OK &&
+		} else if (sasl_server_new("znc", nullptr, nullptr, nullptr, nullptr, m_cbs, 0, &sasl_conn) == SASL_OK &&
 				sasl_checkpass(sasl_conn, sUsername.c_str(), sUsername.size(), sPassword.c_str(), sPassword.size()) == SASL_OK) {
 			m_Cache.AddItem(sCacheKey);
 
@@ -124,13 +124,13 @@ public:
 					if (!pBaseUser) {
 						DEBUG("saslauth: Clone User [" << CloneUser() << "] User not found");
 						delete pUser;
-						pUser = NULL;
+						pUser = nullptr;
 					}
 
 					if (pUser && !pUser->Clone(*pBaseUser, sErr)) {
 						DEBUG("saslauth: Clone User [" << CloneUser() << "] failed: " << sErr);
 						delete pUser;
-						pUser = NULL;
+						pUser = nullptr;
 					}
 				}
 
@@ -142,7 +142,7 @@ public:
 				if (pUser && !CZNC::Get().AddUser(pUser, sErr)) {
 					DEBUG("saslauth: Add user [" << sUsername << "] failed: " << sErr);
 					delete pUser;
-					pUser = NULL;
+					pUser = nullptr;
 				}
 			}
 
diff --git a/modules/dcc.cpp b/modules/dcc.cpp
index dd928476..0da2e6e7 100644
--- a/modules/dcc.cpp
+++ b/modules/dcc.cpp
@@ -24,7 +24,7 @@ class CDCCMod;
 
 class CDCCSock : public CSocket {
 public:
-	CDCCSock(CDCCMod* pMod, const CString& sRemoteNick, const CString& sLocalFile, unsigned long uFileSize = 0, CFile* pFile = NULL);
+	CDCCSock(CDCCMod* pMod, const CString& sRemoteNick, const CString& sLocalFile, unsigned long uFileSize = 0, CFile* pFile = nullptr);
 	CDCCSock(CDCCMod* pMod, const CString& sRemoteNick, const CString& sRemoteIP, unsigned short uRemotePort, const CString& sLocalFile, unsigned long uFileSize);
 	virtual ~CDCCSock();
 
@@ -274,7 +274,7 @@ CDCCSock::CDCCSock(CDCCMod* pMod, const CString& sRemoteNick, const CString& sRe
 	m_uFileSize = uFileSize;
 	m_uBytesSoFar = 0;
 	m_pModule = pMod;
-	m_pFile = NULL;
+	m_pFile = nullptr;
 	m_sLocalFile = sLocalFile;
 	m_bSend = false;
 	m_bNoDelFile = false;
@@ -417,7 +417,7 @@ Csock* CDCCSock::GetSockObj(const CString& sHost, unsigned short uPort) {
 CFile* CDCCSock::OpenFile(bool bWrite) {
 	if ((m_pFile) || (m_sLocalFile.empty())) {
 		m_pModule->PutModule(((bWrite) ? "DCC <- [" : "DCC -> [") + m_sRemoteNick + "][" + m_sLocalFile + "] - Unable to open file.");
-		return NULL;
+		return nullptr;
 	}
 
 	m_pFile = new CFile(m_sLocalFile);
@@ -425,30 +425,30 @@ CFile* CDCCSock::OpenFile(bool bWrite) {
 	if (bWrite) {
 		if (m_pFile->Exists()) {
 			delete m_pFile;
-			m_pFile = NULL;
+			m_pFile = nullptr;
 			m_pModule->PutModule("DCC <- [" + m_sRemoteNick + "] - File already exists [" + m_sLocalFile + "]");
-			return NULL;
+			return nullptr;
 		}
 
 		if (!m_pFile->Open(O_WRONLY | O_TRUNC | O_CREAT)) {
 			delete m_pFile;
-			m_pFile = NULL;
+			m_pFile = nullptr;
 			m_pModule->PutModule("DCC <- [" + m_sRemoteNick + "] - Could not open file [" + m_sLocalFile + "]");
-			return NULL;
+			return nullptr;
 		}
 	} else {
 		if (!m_pFile->IsReg()) {
 			delete m_pFile;
-			m_pFile = NULL;
+			m_pFile = nullptr;
 			m_pModule->PutModule("DCC -> [" + m_sRemoteNick + "] - Not a file [" + m_sLocalFile + "]");
-			return NULL;
+			return nullptr;
 		}
 
 		if (!m_pFile->Open()) {
 			delete m_pFile;
-			m_pFile = NULL;
+			m_pFile = nullptr;
 			m_pModule->PutModule("DCC -> [" + m_sRemoteNick + "] - Could not open file [" + m_sLocalFile + "]");
-			return NULL;
+			return nullptr;
 		}
 
 		// The DCC specs only allow file transfers with files smaller
@@ -456,9 +456,9 @@ CFile* CDCCSock::OpenFile(bool bWrite) {
 		unsigned long long uFileSize = m_pFile->GetSize();
 		if (uFileSize > (unsigned long long) 0xffffffffULL) {
 			delete m_pFile;
-			m_pFile = NULL;
+			m_pFile = nullptr;
 			m_pModule->PutModule("DCC -> [" + m_sRemoteNick + "] - File too large (>4 GiB) [" + m_sLocalFile + "]");
-			return NULL;
+			return nullptr;
 		}
 
 		m_uFileSize = uFileSize;
diff --git a/modules/fail2ban.cpp b/modules/fail2ban.cpp
index f2f483fc..2cffee80 100644
--- a/modules/fail2ban.cpp
+++ b/modules/fail2ban.cpp
@@ -62,7 +62,7 @@ public:
 
 	void OnClientConnect(CZNCSock* pClient, const CString& sHost, unsigned short uPort) override {
 		unsigned int *pCount = m_Cache.GetItem(sHost);
-		if (sHost.empty() || pCount == NULL || *pCount < m_uiAllowedFailed) {
+		if (sHost.empty() || pCount == nullptr || *pCount < m_uiAllowedFailed) {
 			return;
 		}
 
diff --git a/modules/flooddetach.cpp b/modules/flooddetach.cpp
index f1ea4e13..a2fb722d 100644
--- a/modules/flooddetach.cpp
+++ b/modules/flooddetach.cpp
@@ -70,7 +70,7 @@ public:
 
 	void Cleanup() {
 		Limits::iterator it;
-		time_t now = time(NULL);
+		time_t now = time(nullptr);
 
 		for (it = m_chans.begin(); it != m_chans.end(); ++it) {
 			// The timeout for this channel did not expire yet?
@@ -106,7 +106,7 @@ public:
 
 	void Message(CChan& Channel) {
 		Limits::iterator it;
-		time_t now = time(NULL);
+		time_t now = time(nullptr);
 
 		// First: Clean up old entries and reattach where necessary
 		Cleanup();
diff --git a/modules/identfile.cpp b/modules/identfile.cpp
index b9f4f322..b2f7ca55 100644
--- a/modules/identfile.cpp
+++ b/modules/identfile.cpp
@@ -35,8 +35,8 @@ public:
 			"<format>");
 		AddCommand("Show",      static_cast<CModCommand::ModCmdFunc>(&CIdentFileModule::Show));
 
-		m_pISpoofLockFile = NULL;
-		m_pIRCSock = NULL;
+		m_pISpoofLockFile = nullptr;
+		m_pIRCSock = nullptr;
 	}
 
 	virtual ~CIdentFileModule() {
@@ -94,14 +94,14 @@ public:
 	}
 
 	bool WriteISpoof() {
-		if (m_pISpoofLockFile != NULL) {
+		if (m_pISpoofLockFile != nullptr) {
 			return false;
 		}
 
 		m_pISpoofLockFile = new CFile;
 		if (!m_pISpoofLockFile->TryExLock(GetNV("File"), O_RDWR | O_CREAT)) {
 			delete m_pISpoofLockFile;
-			m_pISpoofLockFile = NULL;
+			m_pISpoofLockFile = nullptr;
 			return false;
 		}
 
@@ -112,7 +112,7 @@ public:
 
 		if (!m_pISpoofLockFile->Seek(0) || !m_pISpoofLockFile->Truncate()) {
 			delete m_pISpoofLockFile;
-			m_pISpoofLockFile = NULL;
+			m_pISpoofLockFile = nullptr;
 			return false;
 		}
 
@@ -135,21 +135,21 @@ public:
 		DEBUG("Releasing ident spoof for user/network [" + (m_pIRCSock ? m_pIRCSock->GetNetwork()->GetUser()->GetUserName() + "/" +
 				m_pIRCSock->GetNetwork()->GetName() : "<no user/network>") + "]");
 
-		SetIRCSock(NULL);
+		SetIRCSock(nullptr);
 
-		if (m_pISpoofLockFile != NULL) {
+		if (m_pISpoofLockFile != nullptr) {
 			if (m_pISpoofLockFile->Seek(0) && m_pISpoofLockFile->Truncate()) {
 				m_pISpoofLockFile->Write(m_sOrigISpoof);
 			}
 
 			delete m_pISpoofLockFile;
-			m_pISpoofLockFile = NULL;
+			m_pISpoofLockFile = nullptr;
 		}
 	}
 
 	bool OnLoad(const CString& sArgs, CString& sMessage) override {
-		m_pISpoofLockFile = NULL;
-		m_pIRCSock = NULL;
+		m_pISpoofLockFile = nullptr;
+		m_pIRCSock = nullptr;
 
 		if (GetNV("Format").empty()) {
 			SetNV("Format", "global { reply \"%ident%\" }");
@@ -163,7 +163,7 @@ public:
 	}
 
 	EModRet OnIRCConnecting(CIRCSock *pIRCSock) override {
-		if (m_pISpoofLockFile != NULL) {
+		if (m_pISpoofLockFile != nullptr) {
 			DEBUG("Aborting connection, ident spoof lock file exists");
 			PutModule("Aborting connection, another user or network is currently connecting and using the ident spoof file");
 			return HALTCORE;
diff --git a/modules/keepnick.cpp b/modules/keepnick.cpp
index 57fd95a2..328fe068 100644
--- a/modules/keepnick.cpp
+++ b/modules/keepnick.cpp
@@ -44,7 +44,7 @@ public:
 	~CKeepNickMod() {}
 
 	bool OnLoad(const CString& sArgs, CString& sMessage) override {
-		m_pTimer = NULL;
+		m_pTimer = nullptr;
 
 		// Check if we need to start the timer
 		if (GetNetwork()->IsIRCConnected())
@@ -135,7 +135,7 @@ public:
 
 		m_pTimer->Stop();
 		RemTimer(m_pTimer);
-		m_pTimer = NULL;
+		m_pTimer = nullptr;
 	}
 
 	EModRet OnUserRaw(CString& sLine) override {
@@ -191,7 +191,7 @@ public:
 	}
 
 private:
-	// If this is NULL, we are turned off for some reason
+	// If this is nullptr, we are turned off for some reason
 	CKeepNickTimer* m_pTimer;
 };
 
diff --git a/modules/lastseen.cpp b/modules/lastseen.cpp
index af91b51e..416a111c 100644
--- a/modules/lastseen.cpp
+++ b/modules/lastseen.cpp
@@ -28,7 +28,7 @@ private:
 	}
 
 	void SetTime(const CUser *pUser) {
-		SetNV(pUser->GetUserName(), CString(time(NULL)));
+		SetNV(pUser->GetUserName(), CString(time(nullptr)));
 	}
 
 	const CString FormatLastSeen(const CUser *pUser, const char* sDefault = "") {
@@ -98,7 +98,7 @@ public:
 	bool OnWebRequest(CWebSock& WebSock, const CString& sPageName, CTemplate& Tmpl) override {
 		if (sPageName == "index") {
 			CModules& GModules = CZNC::Get().GetModules();
-			Tmpl["WebAdminLoaded"] = CString(GModules.FindModule("webadmin") != NULL);
+			Tmpl["WebAdminLoaded"] = CString(GModules.FindModule("webadmin") != nullptr);
 
 			MTimeMulti mmSorted;
 			const MUsers& mUsers = CZNC::Get().GetUserMap();
diff --git a/modules/modperl.cpp b/modules/modperl.cpp
index 74a9e42a..d585125a 100644
--- a/modules/modperl.cpp
+++ b/modules/modperl.cpp
@@ -50,7 +50,7 @@ class CModPerl: public CModule {
 	PerlInterpreter *m_pPerl;
 public:
 	MODCONSTRUCTOR(CModPerl) {
-		m_pPerl = NULL;
+		m_pPerl = nullptr;
 	}
 
 #define PSTART dSP; I32 ax; int ret = 0; ENTER; SAVETMPS; PUSHMARK(SP)
@@ -69,7 +69,7 @@ public:
 		int argc = 6;
 		char *pArgv[] = {"", "-T", "-w",
 			"-I", const_cast<char*>(sTmp.c_str()),
-			const_cast<char*>(sModPath.c_str()), NULL};
+			const_cast<char*>(sModPath.c_str()), nullptr};
 		char **argv = pArgv;
 		char *** const pEnviron =
 #if defined(__APPLE__) && defined(__MACH__)
@@ -87,7 +87,7 @@ public:
 			}
 			perl_free(m_pPerl);
 			PERL_SYS_TERM();
-			m_pPerl = NULL;
+			m_pPerl = nullptr;
 			DEBUG(__PRETTY_FUNCTION__ << " can't init perl");
 			return false;
 		}
@@ -319,7 +319,7 @@ void CPerlSocket::ReadLine(const CString& sLine) {
 }
 Csock* CPerlSocket::GetSockObj(const CString& sHost, unsigned short uPort) {
 	CPerlModule* pMod = AsPerlModule(GetModule());
-	Csock* result = NULL;
+	Csock* result = nullptr;
 	if (pMod) {
 		SOCKSTART;
 		PUSH_STR("_Accepted");
diff --git a/modules/modperl/codegen.pl b/modules/modperl/codegen.pl
index 89b7379a..de4e3cf6 100755
--- a/modules/modperl/codegen.pl
+++ b/modules/modperl/codegen.pl
@@ -65,7 +65,7 @@ namespace {
 			if (SWIG_IsOK(res)) {
 				return result;
 			}
-			return NULL;
+			return nullptr;
 		}
 	};
 
@@ -94,7 +94,7 @@ while (<$in>) {
 			when ('bool')			 { $default = 'true' }
 			when ('CModule::EModRet') { $default = 'CONTINUE' }
 			when ('CString')		  { $default = '""' }
-			when (/\*$/)			  { $default = "($type)NULL" }
+			when (/\*$/)			  { $default = "($type)nullptr" }
 		}
 	}
 	my @arg = map {
diff --git a/modules/modperl/module.h b/modules/modperl/module.h
index 88094db3..92bb658e 100644
--- a/modules/modperl/module.h
+++ b/modules/modperl/module.h
@@ -31,7 +31,7 @@ class CPerlModule : public CModule {
 public:
 	CPerlModule(CUser* pUser, CIRCNetwork* pNetwork, const CString& sModName, const CString& sDataPath,
 			SV* perlObj)
-			: CModule(NULL, pUser, pNetwork, sModName, sDataPath) {
+			: CModule(nullptr, pUser, pNetwork, sModName, sDataPath) {
 		m_perlObj = newSVsv(perlObj);
 	}
 	SV* GetPerlObj() {
diff --git a/modules/modperl/pstring.h b/modules/modperl/pstring.h
index bf623a6d..a81e9e8f 100644
--- a/modules/modperl/pstring.h
+++ b/modules/modperl/pstring.h
@@ -54,7 +54,7 @@ class PString : public CString {
 
 		SV* GetSV(bool bMakeMortal = true) const
 		{
-			SV* pSV = NULL;
+			SV* pSV = nullptr;
 			switch (GetType()) {
 				case NUM:
 					pSV = newSVnv(ToDouble());
diff --git a/modules/modpython.cpp b/modules/modpython.cpp
index ed263192..de013ea8 100644
--- a/modules/modpython.cpp
+++ b/modules/modpython.cpp
@@ -54,7 +54,7 @@ public:
 				ptraceback = Py_None;
 			}
 			PyErr_NormalizeException(&ptype, &pvalue, &ptraceback);
-			PyObject* strlist = PyObject_CallFunctionObjArgs(m_PyFormatException, ptype, pvalue, ptraceback, NULL);
+			PyObject* strlist = PyObject_CallFunctionObjArgs(m_PyFormatException, ptype, pvalue, ptraceback, nullptr);
 			Py_CLEAR(ptype);
 			Py_CLEAR(pvalue);
 			Py_CLEAR(ptraceback);
@@ -83,8 +83,8 @@ public:
 
 	MODCONSTRUCTOR(CModPython) {
 		Py_Initialize();
-		m_PyFormatException = NULL;
-		m_PyZNCModule = NULL;
+		m_PyFormatException = nullptr;
+		m_PyZNCModule = nullptr;
 	}
 
 	bool OnLoad(const CString& sArgsi, CString& sMessage) override {
@@ -205,7 +205,7 @@ public:
 				bSuccess = false;
 				return HALT;
 			}
-			PyObject* pyRes = PyObject_CallFunctionObjArgs(pyFunc, pMod->GetPyObj(), NULL);
+			PyObject* pyRes = PyObject_CallFunctionObjArgs(pyFunc, pMod->GetPyObj(), nullptr);
 			if (!pyRes) {
 				sRetMsg = GetPyExceptionStr();
 				DEBUG("modpython: " << sRetMsg);
@@ -351,7 +351,7 @@ public:
 			DEBUG("~CModPython(): couldn't find unload_all: " << sRetMsg);
 			return;
 		}
-		PyObject* pyRes = PyObject_CallFunctionObjArgs(pyFunc, NULL);
+		PyObject* pyRes = PyObject_CallFunctionObjArgs(pyFunc, nullptr);
 		if (!pyRes) {
 			CString sRetMsg = GetPyExceptionStr();
 			DEBUG("modpython tried to unload all modules in its destructor, but: " << sRetMsg);
@@ -434,7 +434,7 @@ void CPySocket::ReadLine(const CString& sLine) {
 }
 
 Csock* CPySocket::GetSockObj(const CString& sHost, unsigned short uPort) {
-	CPySocket* result = NULL;
+	CPySocket* result = nullptr;
 	PyObject* pyRes = PyObject_CallMethod(m_pyObj, const_cast<char*>("_Accepted"), const_cast<char*>("sH"), sHost.c_str(), uPort);
 	if (!pyRes) {
 		CString sRetMsg = m_pModPython->GetPyExceptionStr();
@@ -445,7 +445,7 @@ Csock* CPySocket::GetSockObj(const CString& sHost, unsigned short uPort) {
 	if (!SWIG_IsOK(res)) {
 		DEBUG("python socket was expected to return new socket from OnAccepted, but error=" << res);
 		Close();
-		result = NULL;
+		result = nullptr;
 	}
     if (!result) {
         DEBUG("modpython: OnAccepted didn't return new socket");
diff --git a/modules/modpython/codegen.pl b/modules/modpython/codegen.pl
index 3a77b40d..b18179e4 100755
--- a/modules/modpython/codegen.pl
+++ b/modules/modpython/codegen.pl
@@ -57,7 +57,7 @@ namespace {
 			m_sType = sType;
 		}
 		bool operator()(PyObject* py, T** result) {
-			T* x = NULL;
+			T* x = nullptr;
 			int res = SWIG_ConvertPtr(sv, (void**)&x, SWIG_TypeQuery(m_sType.c_str()), 0);
 			if (SWIG_IsOK(res)) {
 				*result = x;
@@ -218,7 +218,7 @@ bool OnFoo(const CString& x) {
 		Py_CLEAR(pyArg2);
 		return default;
 	}
-	PyObject* pyRes = PyObject_CallMethodObjArgs(m_pyObj, pyName, pyArg1, pyArg2, pyArg3, NULL);
+	PyObject* pyRes = PyObject_CallMethodObjArgs(m_pyObj, pyName, pyArg1, pyArg2, pyArg3, nullptr);
 	if (!pyRes) {
 		CString s = ...;
 		DEBUG("modpython: username/module/OnFoo failed: " << s);
@@ -253,7 +253,7 @@ while (<$in>) {
 			when ('bool')			 { $default = 'true' }
 			when ('CModule::EModRet') { $default = 'CONTINUE' }
 			when ('CString')		  { $default = '""' }
-			when (/\*$/)			  { $default = "($type)NULL" }
+			when (/\*$/)			  { $default = "($type)nullptr" }
 		}
 	}
 	my @arg = map {
@@ -367,7 +367,7 @@ while (<$in>) {
 
 	print $out "\tPyObject* pyRes = PyObject_CallMethodObjArgs(m_pyObj";
 	print $out ", $_->{pyvar}" for @arg;
-	say $out ", NULL);";
+	say $out ", nullptr);";
 	say $out "\tif (!pyRes) {";
 	say $out "\t\tCString sPyErr = m_pModPython->GetPyExceptionStr();";
 	say $out "\t\tDEBUG".'("modpython: " << (GetUser() ? GetUser()->GetUserName() : CString("<no user>")) << "/" << GetModName() << '."\"/$name failed: \" << sPyErr);";
@@ -393,13 +393,13 @@ while (<$in>) {
 				say $out "\t\t}";
 			}
 			when ('CString') {
-				say $out "\t\tCString* p = NULL;";
+				say $out "\t\tCString* p = nullptr;";
 				say $out "\t\tint res = SWIG_AsPtr_std_string(pyRes, &p);";
 				say $out "\t\tif (!SWIG_IsOK(res)) {";
 				say $out "\t\t\tDEBUG(\"modpython: \" << (GetUser() ? GetUser()->GetUserName() : CString(\"<no user>\")) << \"/\" << GetModName() << \"/$name was expected to return '$type' but error=\" << res);";
 				say $out "\t\t\tresult = $default;";
 				say $out "\t\t} else if (!p) {";
-				say $out "\t\t\tDEBUG(\"modpython: \" << (GetUser() ? GetUser()->GetUserName() : CString(\"<no user>\")) << \"/\" << GetModName() << \"/$name was expected to return '$type' but returned NULL\");";
+				say $out "\t\t\tDEBUG(\"modpython: \" << (GetUser() ? GetUser()->GetUserName() : CString(\"<no user>\")) << \"/\" << GetModName() << \"/$name was expected to return '$type' but returned nullptr\");";
 				say $out "\t\t\tresult = $default;";
 				say $out "\t\t} else result = *p;";
 				say $out "\t\tif (SWIG_IsNewObj(res)) free((char*)p); // Don't ask me, that's how SWIG works...";
diff --git a/modules/modpython/modpython.i b/modules/modpython/modpython.i
index ed578cd0..9bb9904c 100644
--- a/modules/modpython/modpython.i
+++ b/modules/modpython/modpython.i
@@ -206,12 +206,12 @@ class CPyRetBool {
     PyObject* WriteBytes(PyObject* data) {
         if (!PyBytes_Check(data)) {
             PyErr_SetString(PyExc_TypeError, "socket.WriteBytes needs bytes as argument");
-            return NULL;
+            return nullptr;
         }
         char* buffer;
         Py_ssize_t length;
         if (-1 == PyBytes_AsStringAndSize(data, &buffer, &length)) {
-            return NULL;
+            return nullptr;
         }
         if ($self->Write(buffer, length)) {
             Py_RETURN_TRUE;
diff --git a/modules/modpython/module.h b/modules/modpython/module.h
index 2c741880..0a3e2b81 100644
--- a/modules/modpython/module.h
+++ b/modules/modpython/module.h
@@ -33,7 +33,7 @@ class CPyModule : public CModule {
 public:
 	CPyModule(CUser* pUser, CIRCNetwork* pNetwork, const CString& sModName, const CString& sDataPath,
 			PyObject* pyObj, CModPython* pModPython)
-			: CModule(NULL, pUser, pNetwork, sModName, sDataPath) {
+			: CModule(nullptr, pUser, pNetwork, sModName, sDataPath) {
 		m_pyObj = pyObj;
 		Py_INCREF(pyObj);
 		m_pModPython = pModPython;
diff --git a/modules/modtcl.cpp b/modules/modtcl.cpp
index ebd72954..6ff4044a 100644
--- a/modules/modtcl.cpp
+++ b/modules/modtcl.cpp
@@ -30,7 +30,7 @@ using std::map;
 #define BADARGS(nl, nh, example) do {                               \
 	if ((argc < (nl)) || (argc > (nh))) {                       \
 		Tcl_AppendResult(irp, "wrong # args: should be \"", \
-			argv[0], (example), "\"", NULL);            \
+			argv[0], (example), "\"", nullptr);            \
 		return TCL_ERROR;                                   \
 	}                                                           \
 } while (0)
@@ -40,7 +40,7 @@ class CModTcl;
 class CModTclTimer : public CTimer {
 public:
 
-	CModTclTimer(CModule* pModule, unsigned int uInterval, unsigned int uCycles, const CString& sLabel, const CString& sDescription) : CTimer(pModule, uInterval, uCycles, sLabel, sDescription), m_pParent(NULL) {}
+	CModTclTimer(CModule* pModule, unsigned int uInterval, unsigned int uCycles, const CString& sLabel, const CString& sDescription) : CTimer(pModule, uInterval, uCycles, sLabel, sDescription), m_pParent(nullptr) {}
 	virtual ~CModTclTimer() {}
 protected:
 	void RunJob() override;
@@ -50,7 +50,7 @@ protected:
 class CModTclStartTimer : public CTimer {
 public:
 
-	CModTclStartTimer(CModule* pModule, unsigned int uInterval, unsigned int uCycles, const CString& sLabel, const CString& sDescription) : CTimer(pModule, uInterval, uCycles, sLabel, sDescription), m_pParent(NULL) {}
+	CModTclStartTimer(CModule* pModule, unsigned int uInterval, unsigned int uCycles, const CString& sLabel, const CString& sDescription) : CTimer(pModule, uInterval, uCycles, sLabel, sDescription), m_pParent(nullptr) {}
 	virtual ~CModTclStartTimer() {}
 protected:
 	void RunJob() override;
@@ -61,7 +61,7 @@ protected:
 class CModTcl : public CModule {
 public:
 	MODCONSTRUCTOR(CModTcl) {
-		interp = NULL;
+		interp = nullptr;
 	}
 
 	virtual ~CModTcl() {
@@ -87,32 +87,32 @@ public:
 
 		interp = Tcl_CreateInterp();
 		Tcl_Init(interp);
-		Tcl_CreateCommand(interp, "Binds::ProcessPubm", tcl_Bind, this, NULL);
-		Tcl_CreateCommand(interp, "Binds::ProcessMsgm", tcl_Bind, this, NULL);
-		Tcl_CreateCommand(interp, "Binds::ProcessTime", tcl_Bind, this, NULL);
-		Tcl_CreateCommand(interp, "Binds::ProcessEvnt", tcl_Bind, this, NULL);
-		Tcl_CreateCommand(interp, "Binds::ProcessNick", tcl_Bind, this, NULL);
-		Tcl_CreateCommand(interp, "Binds::ProcessKick", tcl_Bind, this, NULL);
-		Tcl_CreateCommand(interp, "PutIRC", tcl_PutIRC, this, NULL);
-		Tcl_CreateCommand(interp, "PutModule", tcl_PutModule, this, NULL);
-		Tcl_CreateCommand(interp, "PutStatus", tcl_PutStatus, this, NULL);
-		Tcl_CreateCommand(interp, "PutStatusNotice", tcl_PutStatusNotice, this, NULL);
-		Tcl_CreateCommand(interp, "PutUser", tcl_PutUser, this, NULL);
+		Tcl_CreateCommand(interp, "Binds::ProcessPubm", tcl_Bind, this, nullptr);
+		Tcl_CreateCommand(interp, "Binds::ProcessMsgm", tcl_Bind, this, nullptr);
+		Tcl_CreateCommand(interp, "Binds::ProcessTime", tcl_Bind, this, nullptr);
+		Tcl_CreateCommand(interp, "Binds::ProcessEvnt", tcl_Bind, this, nullptr);
+		Tcl_CreateCommand(interp, "Binds::ProcessNick", tcl_Bind, this, nullptr);
+		Tcl_CreateCommand(interp, "Binds::ProcessKick", tcl_Bind, this, nullptr);
+		Tcl_CreateCommand(interp, "PutIRC", tcl_PutIRC, this, nullptr);
+		Tcl_CreateCommand(interp, "PutModule", tcl_PutModule, this, nullptr);
+		Tcl_CreateCommand(interp, "PutStatus", tcl_PutStatus, this, nullptr);
+		Tcl_CreateCommand(interp, "PutStatusNotice", tcl_PutStatusNotice, this, nullptr);
+		Tcl_CreateCommand(interp, "PutUser", tcl_PutUser, this, nullptr);
 
-		Tcl_CreateCommand(interp, "GetCurNick", tcl_GetCurNick, this, NULL);
-		Tcl_CreateCommand(interp, "GetUsername", tcl_GetUsername, this, NULL);
-		Tcl_CreateCommand(interp, "GetRealName", tcl_GetRealName, this, NULL);
-		Tcl_CreateCommand(interp, "GetVHost", tcl_GetBindHost, this, NULL);
-		Tcl_CreateCommand(interp, "GetBindHost", tcl_GetBindHost, this, NULL);
-		Tcl_CreateCommand(interp, "GetChans", tcl_GetChans, this, NULL);
-		Tcl_CreateCommand(interp, "GetChannelUsers", tcl_GetChannelUsers, this, NULL);
-		Tcl_CreateCommand(interp, "GetChannelModes", tcl_GetChannelModes, this, NULL);
-		Tcl_CreateCommand(interp, "GetServer", tcl_GetServer, this, NULL);
-		Tcl_CreateCommand(interp, "GetServerOnline", tcl_GetServerOnline, this, NULL);
-		Tcl_CreateCommand(interp, "GetModules", tcl_GetModules, this, NULL);
-		Tcl_CreateCommand(interp, "GetClientCount", tcl_GetClientCount, this, NULL);
+		Tcl_CreateCommand(interp, "GetCurNick", tcl_GetCurNick, this, nullptr);
+		Tcl_CreateCommand(interp, "GetUsername", tcl_GetUsername, this, nullptr);
+		Tcl_CreateCommand(interp, "GetRealName", tcl_GetRealName, this, nullptr);
+		Tcl_CreateCommand(interp, "GetVHost", tcl_GetBindHost, this, nullptr);
+		Tcl_CreateCommand(interp, "GetBindHost", tcl_GetBindHost, this, nullptr);
+		Tcl_CreateCommand(interp, "GetChans", tcl_GetChans, this, nullptr);
+		Tcl_CreateCommand(interp, "GetChannelUsers", tcl_GetChannelUsers, this, nullptr);
+		Tcl_CreateCommand(interp, "GetChannelModes", tcl_GetChannelModes, this, nullptr);
+		Tcl_CreateCommand(interp, "GetServer", tcl_GetServer, this, nullptr);
+		Tcl_CreateCommand(interp, "GetServerOnline", tcl_GetServerOnline, this, nullptr);
+		Tcl_CreateCommand(interp, "GetModules", tcl_GetModules, this, nullptr);
+		Tcl_CreateCommand(interp, "GetClientCount", tcl_GetClientCount, this, nullptr);
 
-		Tcl_CreateCommand(interp, "exit", tcl_exit, this, NULL);
+		Tcl_CreateCommand(interp, "exit", tcl_exit, this, nullptr);
 
 		if (!sMyArgs.empty()) {
 			i = Tcl_EvalFile(interp, sMyArgs.c_str());
diff --git a/modules/notify_connect.cpp b/modules/notify_connect.cpp
index b9ece199..b05177ff 100644
--- a/modules/notify_connect.cpp
+++ b/modules/notify_connect.cpp
@@ -31,7 +31,7 @@ public:
 
 private:
 	void SendAdmins(const CString &msg) {
-		CZNC::Get().Broadcast(msg, true, NULL, GetClient());
+		CZNC::Get().Broadcast(msg, true, nullptr, GetClient());
 	}
 };
 
diff --git a/modules/partyline.cpp b/modules/partyline.cpp
index 5ec57d08..834b2c15 100644
--- a/modules/partyline.cpp
+++ b/modules/partyline.cpp
@@ -431,7 +431,7 @@ public:
 				}
 			}
 
-			SendNickList(pUser, NULL, ssNicks, pChannel->GetName());
+			SendNickList(pUser, nullptr, ssNicks, pChannel->GetName());
 
 			/* Tell the other clients we have op or voice, the current user's clients already know from NAMES list */
 
@@ -464,7 +464,7 @@ public:
 		}
 
 		if (cPrefix == CHAN_PREFIX_1C) {
-			if (FindChannel(sTarget) == NULL) {
+			if (FindChannel(sTarget) == nullptr) {
 				pClient->PutClient(":" + GetIRCServer(pNetwork) + " 401 " + pClient->GetNick() + " " + sTarget + " :No such channel");
 				return HALT;
 			}
@@ -526,10 +526,10 @@ public:
 		return "irc.znc.in";
 	}
 
-	bool PutChan(const CString& sChan, const CString& sLine, bool bIncludeCurUser = true, bool bIncludeClient = true, CUser* pUser = NULL, CClient* pClient = NULL) {
+	bool PutChan(const CString& sChan, const CString& sLine, bool bIncludeCurUser = true, bool bIncludeClient = true, CUser* pUser = nullptr, CClient* pClient = nullptr) {
 		CPartylineChannel* pChannel = FindChannel(sChan);
 
-		if (pChannel != NULL) {
+		if (pChannel != nullptr) {
 			PutChan(pChannel->GetNicks(), sLine, bIncludeCurUser, bIncludeClient, pUser, pClient);
 			return true;
 		}
@@ -537,7 +537,7 @@ public:
 		return false;
 	}
 
-	void PutChan(const set<CString>& ssNicks, const CString& sLine, bool bIncludeCurUser = true, bool bIncludeClient = true, CUser* pUser = NULL, CClient* pClient = NULL) {
+	void PutChan(const set<CString>& ssNicks, const CString& sLine, bool bIncludeCurUser = true, bool bIncludeClient = true, CUser* pUser = nullptr, CClient* pClient = nullptr) {
 		const map<CString, CUser*>& msUsers = CZNC::Get().GetUserMap();
 
 		if (!pUser)
@@ -549,7 +549,7 @@ public:
 			if (ssNicks.find(it->first) != ssNicks.end()) {
 				if (it->second == pUser) {
 					if (bIncludeCurUser) {
-						it->second->PutAllUser(sLine, NULL, (bIncludeClient ? NULL : pClient));
+						it->second->PutAllUser(sLine, nullptr, (bIncludeClient ? nullptr : pClient));
 					}
 				} else {
 					it->second->PutAllUser(sLine);
@@ -609,7 +609,7 @@ public:
 				return *it;
 		}
 
-		return NULL;
+		return nullptr;
 	}
 
 	CPartylineChannel* GetChannel(const CString& sChannel) {
diff --git a/modules/route_replies.cpp b/modules/route_replies.cpp
index 45a883c6..22274b02 100644
--- a/modules/route_replies.cpp
+++ b/modules/route_replies.cpp
@@ -33,21 +33,21 @@ static const struct {
 		{"315", true},  /* rfc1459 RPL_ENDOFWHO */
 		{"354", false}, // e.g. Quaknet uses this for WHO #chan %n
 		{"403", true}, // No such chan
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"LIST", {
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
 		{"321", false},  /* rfc1459 RPL_LISTSTART */
 		{"322", false},  /* rfc1459 RPL_LIST */
 		{"323", true},  /* rfc1459 RPL_LISTEND */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"NAMES", {
 		{"353", false},  /* rfc1459 RPL_NAMREPLY */
 		{"366", true},  /* rfc1459 RPL_ENDOFNAMES */
 		// No such nick/channel
 		{"401", true},
-		{NULL, true},
+		{nullptr, true},
 	}},
 	{"LUSERS", {
 		{"251", false},  /* rfc1459 RPL_LUSERCLIENT */
@@ -59,7 +59,7 @@ static const struct {
 		{"266", true},
 		// We don't handle 250 here since some IRCds don't sent it
 		//{"250", true},
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"WHOIS", {
 		{"311", false},  /* rfc1459 RPL_WHOISUSER */
@@ -81,23 +81,23 @@ static const struct {
 		{"401", true},  /* rfc1459 ERR_NOSUCHNICK */
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
 		{"431", true},  /* rfc1459 ERR_NONICKNAMEGIVEN */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"PING", {
 		{"PONG", true},
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
 		{"409", true},  /* rfc1459 ERR_NOORIGIN */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"USERHOST", {
 		{"302", true},
 		{"461", true},  /* rfc1459 ERR_NEEDMOREPARAMS */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"TIME", {
 		{"391", true},  /* rfc1459 RPL_TIME */
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"WHOWAS", {
 		{"406", false},  /* rfc1459 ERR_WASNOSUCHNICK */
@@ -105,18 +105,18 @@ static const struct {
 		{"314", false},  /* rfc1459 RPL_WHOWASUSER */
 		{"369", true},  /* rfc1459 RPL_ENDOFWHOWAS */
 		{"431", true},  /* rfc1459 ERR_NONICKNAMEGIVEN */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"ISON", {
 		{"303", true},  /* rfc1459 RPL_ISON */
 		{"461", true},  /* rfc1459 ERR_NEEDMOREPARAMS */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"LINKS", {
 		{"364", false},  /* rfc1459 RPL_LINKS */
 		{"365", true},  /* rfc1459 RPL_ENDOFLINKS */
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"MAP", {
 		{"006", false},
@@ -127,7 +127,7 @@ static const struct {
 		{"017", true},
 		{"007", true},
 		{"481", true},  /* rfc1459 ERR_NOPRIVILEGES */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"TRACE", {
 		{"200", false},  /* rfc1459 RPL_TRACELINK */
@@ -141,7 +141,7 @@ static const struct {
 		{"261", false},  /* rfc1459 RPL_TRACELOG */
 		{"262", true},
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
-		{NULL, true}
+		{nullptr, true}
 	}},
 	{"USERS", {
 		{"265", false},
@@ -153,7 +153,7 @@ static const struct {
 		{"402", true},  /* rfc1459 ERR_NOSUCHSERVER */
 		{"424", true},  /* rfc1459 ERR_FILEERROR */
 		{"446", true},  /* rfc1459 ERR_USERSDISABLED */
-		{NULL, true},
+		{nullptr, true},
 	}},
 	{"METADATA", {
 		{"761", false},  /* ircv3.2 RPL_KEYVALUE */
@@ -163,7 +163,7 @@ static const struct {
 		{"767", true},  /* ircv3.2 ERR_KEYINVALID */
 		{"768", true},  /* ircv3.2 ERR_KEYNOTSET */
 		{"769", true},  /* ircv3.2 ERR_KEYNOPERMISSION */
-		{NULL, true},
+		{nullptr, true},
 	}},
 	// This is just a list of all possible /mode replies stuffed together.
 	// Since there should never be more than one of these going on, this
@@ -184,10 +184,10 @@ static const struct {
 		{"472", true},  /* rfc1459 ERR_UNKNOWNMODE */
 		{"501", true},  /* rfc1459 ERR_UMODEUNKNOWNFLAG */
 		{"502", true},  /* rfc1459 ERR_USERSDONTMATCH */
-		{NULL, true},
+		{nullptr, true},
 	 }},
 	// END (last item!)
-	{NULL, {{NULL, true}}}
+	{nullptr, {{nullptr, true}}}
 };
 
 class CRouteTimeout : public CTimer {
@@ -213,8 +213,8 @@ class CRouteRepliesMod : public CModule
 public:
 	MODCONSTRUCTOR(CRouteRepliesMod)
 	{
-		m_pDoing = NULL;
-		m_pReplies = NULL;
+		m_pDoing = nullptr;
+		m_pReplies = nullptr;
 
 		AddHelpCommand();
 		AddCommand("Silent", static_cast<CModCommand::ModCmdFunc>(&CRouteRepliesMod::SilentCommand),
@@ -238,8 +238,8 @@ public:
 
 	void OnIRCConnected() override
 	{
-		m_pDoing = NULL;
-		m_pReplies = NULL;
+		m_pDoing = nullptr;
+		m_pReplies = nullptr;
 		m_vsPending.clear();
 
 		// No way we get a reply, so stop the timer (If it's running)
@@ -259,8 +259,8 @@ public:
 			// The replies which aren't received yet will be
 			// broadcasted to everyone, but at least nothing breaks
 			RemTimer("RouteTimeout");
-			m_pDoing = NULL;
-			m_pReplies = NULL;
+			m_pDoing = nullptr;
+			m_pReplies = nullptr;
 		}
 
 		it = m_vsPending.find(GetClient());
@@ -292,7 +292,7 @@ public:
 			}
 		}
 
-		while (m_pReplies[i].szReply != NULL) {
+		while (m_pReplies[i].szReply != nullptr) {
 			if (m_pReplies[i].szReply == sCmd) {
 				if (RouteReply(sLine, m_pReplies[i].bLastResponse, sCmd == "353"))
 					return HALTCORE;
@@ -349,7 +349,7 @@ public:
 			// Fall through to the next loop
 		}
 
-		for (size_t i = 0; vRouteReplies[i].szRequest != NULL; i++) {
+		for (size_t i = 0; vRouteReplies[i].szRequest != nullptr; i++) {
 			if (vRouteReplies[i].szRequest == sCmd) {
 				struct queued_req req = {
 					sLine, vRouteReplies[i].vReplies
@@ -375,7 +375,7 @@ public:
 			PutModule("Last request: " + m_sLastRequest);
 			PutModule("Expected replies: ");
 
-			for (size_t i = 0; m_pReplies[i].szReply != NULL; i++) {
+			for (size_t i = 0; m_pReplies[i].szReply != nullptr; i++) {
 				if (m_pReplies[i].bLastResponse)
 					PutModule(m_pReplies[i].szReply +
 							CString(" (last)"));
@@ -384,8 +384,8 @@ public:
 			}
 		}
 
-		m_pDoing = NULL;
-		m_pReplies = NULL;
+		m_pDoing = nullptr;
+		m_pReplies = nullptr;
 		SendRequest();
 	}
 
@@ -405,8 +405,8 @@ private:
 			// Stop the timeout
 			RemTimer("RouteTimeout");
 
-			m_pDoing = NULL;
-			m_pReplies = NULL;
+			m_pDoing = nullptr;
+			m_pReplies = nullptr;
 			SendRequest();
 		}
 
diff --git a/modules/sasl.cpp b/modules/sasl.cpp
index 6e331df2..3c72a7b1 100644
--- a/modules/sasl.cpp
+++ b/modules/sasl.cpp
@@ -24,7 +24,7 @@ static const struct {
 } SupportedMechanisms[] = {
 	{ "EXTERNAL",           "TLS certificate, for use with the *cert module", false },
 	{ "PLAIN",              "Plain text negotiation, this should work always if the network supports SASL", true },
-	{ NULL, NULL, false }
+	{ nullptr, nullptr, false }
 };
 
 #define NV_REQUIRE_AUTH     "require_auth"
@@ -86,7 +86,7 @@ public:
 		Mechanisms.AddColumn("Mechanism");
 		Mechanisms.AddColumn("Description");
 
-		for (size_t i = 0; SupportedMechanisms[i].szName != NULL; i++) {
+		for (size_t i = 0; SupportedMechanisms[i].szName != nullptr; i++) {
 			Mechanisms.AddRow();
 			Mechanisms.SetCell("Mechanism",   SupportedMechanisms[i].szName);
 			Mechanisms.SetCell("Description", SupportedMechanisms[i].szDescription);
@@ -137,7 +137,7 @@ public:
 	}
 
 	bool SupportsMechanism(const CString& sMechanism) const {
-		for (size_t i = 0; SupportedMechanisms[i].szName != NULL; i++) {
+		for (size_t i = 0; SupportedMechanisms[i].szName != nullptr; i++) {
 			if (sMechanism.Equals(SupportedMechanisms[i].szName)) {
 				return true;
 			}
@@ -150,7 +150,7 @@ public:
 		if (GetNV(NV_MECHANISMS).empty()) {
 			CString sDefaults = "";
 
-			for (size_t i = 0; SupportedMechanisms[i].szName != NULL; i++) {
+			for (size_t i = 0; SupportedMechanisms[i].szName != nullptr; i++) {
 				if (SupportedMechanisms[i].bDefault) {
 					if (!sDefaults.empty()) {
 						sDefaults += " ";
diff --git a/modules/savebuff.cpp b/modules/savebuff.cpp
index c2bd3f4e..37db0b27 100644
--- a/modules/savebuff.cpp
+++ b/modules/savebuff.cpp
@@ -323,7 +323,7 @@ public:
 #ifdef LEGACY_SAVEBUFF /* event logging is deprecated now in savebuf. Use buffextras module along side of this */
 	CString SpoofChanMsg(const CString & sChannel, const CString & sMesg)
 	{
-		CString sReturn = ":*" + GetModName() + "!znc@znc.in PRIVMSG " + sChannel + " :" + CString(time(NULL)) + " " + sMesg;
+		CString sReturn = ":*" + GetModName() + "!znc@znc.in PRIVMSG " + sChannel + " :" + CString(time(nullptr)) + " " + sMesg;
 		return(sReturn);
 	}
 
diff --git a/modules/shell.cpp b/modules/shell.cpp
index 06f69cfc..b1f7429b 100644
--- a/modules/shell.cpp
+++ b/modules/shell.cpp
@@ -122,7 +122,7 @@ void CShellSock::ReadLine(const CString& sData) {
 
 	m_pParent->SetClient(m_pClient);
 	m_pParent->PutShell(sLine);
-	m_pParent->SetClient(NULL);
+	m_pParent->SetClient(nullptr);
 }
 
 void CShellSock::Disconnected() {
@@ -134,7 +134,7 @@ void CShellSock::Disconnected() {
 
 	m_pParent->SetClient(m_pClient);
 	m_pParent->PutShell("znc$");
-	m_pParent->SetClient(NULL);
+	m_pParent->SetClient(nullptr);
 }
 
 template<> void TModInfo<CShellMod>(CModInfo& Info) {
diff --git a/modules/simple_away.cpp b/modules/simple_away.cpp
index c07bd14f..57d6e7aa 100644
--- a/modules/simple_away.cpp
+++ b/modules/simple_away.cpp
@@ -183,7 +183,7 @@ private:
 		if (sReason.empty())
 			sReason = SIMPLE_AWAY_DEFAULT_REASON;
 
-		time_t iTime = time(NULL);
+		time_t iTime = time(nullptr);
 		CString sTime = CUtils::CTime(iTime, GetUser()->GetTimezone());
 		sReason.Replace("%s", sTime);
 
diff --git a/modules/webadmin.cpp b/modules/webadmin.cpp
index 69588ead..0de853a6 100644
--- a/modules/webadmin.cpp
+++ b/modules/webadmin.cpp
@@ -28,7 +28,7 @@ using std::map;
 
 /* Stuff to be able to write this:
    // i will be name of local variable, see below
-   // pUser can be NULL if only global modules are needed
+   // pUser can be nullptr if only global modules are needed
    FOR_EACH_MODULE(i, pUser) {
        // i is local variable of type CModules::iterator,
 	   // so *i has type CModule*
@@ -173,7 +173,7 @@ public:
 
 		if (sUsername.empty()) {
 			WebSock.PrintErrorPage("Invalid Submission [Username is required]");
-			return NULL;
+			return nullptr;
 		}
 
 		if (pUser) {
@@ -185,7 +185,7 @@ public:
 
 		if (sArg != WebSock.GetParam("password2")) {
 			WebSock.PrintErrorPage("Invalid Submission [Passwords do not match]");
-			return NULL;
+			return nullptr;
 		}
 
 		CUser* pNewUser = new CUser(sUsername);
@@ -308,7 +308,7 @@ public:
 			pNewUser->SetMaxNetworks(pUser->MaxNetworks());
 		}
 
-		// If pUser is not NULL, we are editing an existing user.
+		// If pUser is not nullptr, we are editing an existing user.
 		// Users must not be able to change their own admin flag.
 		if (pUser != CZNC::Get().FindUser(WebSock.GetUser())) {
 			pNewUser->SetAdmin(WebSock.GetParam("isadmin").ToBool());
@@ -343,7 +343,7 @@ public:
 					CString sArgs = WebSock.GetParam("modargs_" + sModName);
 
 					try {
-						if (!pNewUser->GetModules().LoadModule(sModName, sArgs, CModInfo::UserModule, pNewUser, NULL, sModRet)) {
+						if (!pNewUser->GetModules().LoadModule(sModName, sArgs, CModInfo::UserModule, pNewUser, nullptr, sModRet)) {
 							sModLoadError = "Unable to load module [" + sModName + "] [" + sModRet + "]";
 						}
 					} catch (...) {
@@ -366,7 +366,7 @@ public:
 				CString sModLoadError;
 
 				try {
-					if (!pNewUser->GetModules().LoadModule(sModName, sArgs, CModInfo::UserModule, pNewUser, NULL, sModRet)) {
+					if (!pNewUser->GetModules().LoadModule(sModName, sArgs, CModInfo::UserModule, pNewUser, nullptr, sModRet)) {
 						sModLoadError = "Unable to load module [" + sModName + "] [" + sModRet + "]";
 					}
 				} catch (...) {
@@ -409,7 +409,7 @@ public:
 
 	CIRCNetwork* SafeGetNetworkFromParam(CWebSock& WebSock) {
 		CUser* pUser = CZNC::Get().FindUser(SafeGetUserNameParam(WebSock));
-		CIRCNetwork* pNetwork = NULL;
+		CIRCNetwork* pNetwork = nullptr;
 
 		if (pUser) {
 			pNetwork = pUser->FindNetwork(SafeGetNetworkParam(WebSock));
@@ -614,7 +614,7 @@ public:
 		return false;
 	}
 
-	bool ChanPage(CWebSock& WebSock, CTemplate& Tmpl, CIRCNetwork* pNetwork, CChan* pChan = NULL) {
+	bool ChanPage(CWebSock& WebSock, CTemplate& Tmpl, CIRCNetwork* pNetwork, CChan* pChan = nullptr) {
 		std::shared_ptr<CWebSession> spSession = WebSock.GetSession();
 		Tmpl.SetFile("add_edit_chan.tmpl");
 		CUser* pUser = pNetwork->GetUser();
@@ -760,7 +760,7 @@ public:
 		return true;
 	}
 
-	bool NetworkPage(CWebSock& WebSock, CTemplate& Tmpl, CUser* pUser, CIRCNetwork* pNetwork = NULL) {
+	bool NetworkPage(CWebSock& WebSock, CTemplate& Tmpl, CUser* pUser, CIRCNetwork* pNetwork = nullptr) {
 		std::shared_ptr<CWebSession> spSession = WebSock.GetSession();
 		Tmpl.SetFile("add_edit_network.tmpl");
 
@@ -789,11 +789,11 @@ public:
 
 				// Check if module is loaded globally
 				l["CanBeLoadedGlobally"] = CString(Info.SupportsType(CModInfo::GlobalModule));
-				l["LoadedGlobally"] = CString(CZNC::Get().GetModules().FindModule(Info.GetName()) != NULL);
+				l["LoadedGlobally"] = CString(CZNC::Get().GetModules().FindModule(Info.GetName()) != nullptr);
 
 				// Check if module is loaded by user
 				l["CanBeLoadedByUser"] = CString(Info.SupportsType(CModInfo::UserModule));
-				l["LoadedByUser"] = CString(pUser->GetModules().FindModule(Info.GetName()) != NULL);
+				l["LoadedByUser"] = CString(pUser->GetModules().FindModule(Info.GetName()) != nullptr);
 
 				if (!spSession->IsAdmin() && pUser->DenyLoadMod()) {
 					l["Disabled"] = "true";
@@ -1178,7 +1178,7 @@ public:
 		return false;
 	}
 
-	bool UserPage(CWebSock& WebSock, CTemplate& Tmpl, CUser* pUser = NULL) {
+	bool UserPage(CWebSock& WebSock, CTemplate& Tmpl, CUser* pUser = nullptr) {
 		std::shared_ptr<CWebSession> spSession = WebSock.GetSession();
 		Tmpl.SetFile("add_edit_user.tmpl");
 
@@ -1349,7 +1349,7 @@ public:
 				l["HasArgs"] = CString(Info.GetHasArgs());
 				l["ArgsHelpText"] = Info.GetArgsHelpText();
 
-				CModule *pModule = NULL;
+				CModule *pModule = nullptr;
 				if (pUser) {
 					pModule = pUser->GetModules().FindModule(Info.GetName());
 					// Check if module is loaded by all or some networks
@@ -1375,7 +1375,7 @@ public:
 				}
 				l["CanBeLoadedGlobally"] = CString(Info.SupportsType(CModInfo::GlobalModule));
 				// Check if module is loaded globally
-				l["LoadedGlobally"] = CString(CZNC::Get().GetModules().FindModule(Info.GetName()) != NULL);
+				l["LoadedGlobally"] = CString(CZNC::Get().GetModules().FindModule(Info.GetName()) != nullptr);
 
 				if (!spSession->IsAdmin() && pUser && pUser->DenyLoadMod()) {
 					l["Disabled"] = "true";
@@ -1442,7 +1442,7 @@ public:
 			return true;
 		}
 
-		/* If pUser is NULL, we are adding a user, else we are editing this one */
+		/* If pUser is nullptr, we are adding a user, else we are editing this one */
 
 		CString sUsername = WebSock.GetParam("user");
 		if (!pUser && CZNC::Get().FindUser(sUsername)) {
@@ -1867,11 +1867,11 @@ public:
 
 				CModule *pMod = CZNC::Get().GetModules().FindModule(sModName);
 				if (!pMod) {
-					if (!CZNC::Get().GetModules().LoadModule(sModName, sArgs, CModInfo::GlobalModule, NULL, NULL, sModRet)) {
+					if (!CZNC::Get().GetModules().LoadModule(sModName, sArgs, CModInfo::GlobalModule, nullptr, nullptr, sModRet)) {
 						sModLoadError = "Unable to load module [" + sModName + "] [" + sModRet + "]";
 					}
 				} else if (pMod->GetArgs() != sArgs) {
-					if (!CZNC::Get().GetModules().ReloadModule(sModName, sArgs, NULL, NULL, sModRet)) {
+					if (!CZNC::Get().GetModules().ReloadModule(sModName, sArgs, nullptr, nullptr, sModRet)) {
 						sModLoadError = "Unable to reload module [" + sModName + "] [" + sModRet + "]";
 					}
 				}
diff --git a/src/Chan.cpp b/src/Chan.cpp
index 63f12d83..d419f3b8 100644
--- a/src/Chan.cpp
+++ b/src/Chan.cpp
@@ -583,7 +583,7 @@ void CChan::SendBuffer(CClient* pClient) {
 
 void CChan::SendBuffer(CClient* pClient, const CBuffer& Buffer) {
 	if (m_pNetwork && m_pNetwork->IsUserAttached()) {
-		// in the event that pClient is NULL, need to send this to all clients for the user
+		// in the event that pClient is nullptr, need to send this to all clients for the user
 		// I'm presuming here that pClient is listed inside vClients thus vClients at this
 		// point can't be empty.
 		//
@@ -594,7 +594,7 @@ void CChan::SendBuffer(CClient* pClient, const CBuffer& Buffer) {
 		// 4. OnChanBufferEnding
 		//
 		// With the exception of ClearBuffer(), this needs to happen per client, and
-		// if pClient is not NULL, the loops break after the first iteration.
+		// if pClient is not nullptr, the loops break after the first iteration.
 		//
 		// Rework this if you like ...
 		if (!Buffer.IsEmpty()) {
diff --git a/src/Client.cpp b/src/Client.cpp
index 1a09cdd3..fe8d5d68 100644
--- a/src/Client.cpp
+++ b/src/Client.cpp
@@ -25,12 +25,12 @@ using std::map;
 using std::vector;
 
 #define CALLMOD(MOD, CLIENT, USER, NETWORK, FUNC) {  \
-	CModule *pModule = NULL;  \
+	CModule *pModule = nullptr;  \
 	if (NETWORK && (pModule = (NETWORK)->GetModules().FindModule(MOD))) {  \
 		try {  \
 			pModule->SetClient(CLIENT);  \
 			pModule->FUNC;  \
-			pModule->SetClient(NULL);  \
+			pModule->SetClient(nullptr);  \
 		} catch (const CModule::EModException& e) {  \
 			if (e == CModule::UNLOAD) {  \
 				(NETWORK)->GetModules().UnloadModule(MOD);  \
@@ -41,8 +41,8 @@ using std::vector;
 			pModule->SetClient(CLIENT);  \
 			pModule->SetNetwork(NETWORK);  \
 			pModule->FUNC;  \
-			pModule->SetClient(NULL);  \
-			pModule->SetNetwork(NULL);  \
+			pModule->SetClient(nullptr);  \
+			pModule->SetNetwork(nullptr);  \
 		} catch (const CModule::EModException& e) {  \
 			if (e == CModule::UNLOAD) {  \
 				(USER)->GetModules().UnloadModule(MOD);  \
@@ -54,9 +54,9 @@ using std::vector;
 			pModule->SetNetwork(NETWORK);  \
 			pModule->SetUser(USER);  \
 			pModule->FUNC;  \
-			pModule->SetClient(NULL);  \
-			pModule->SetNetwork(NULL);  \
-			pModule->SetUser(NULL);  \
+			pModule->SetClient(nullptr);  \
+			pModule->SetNetwork(nullptr);  \
+			pModule->SetUser(nullptr);  \
 		} catch (const CModule::EModException& e) {  \
 			if (e == CModule::UNLOAD) {  \
 					CZNC::Get().GetModules().UnloadModule(MOD);  \
diff --git a/src/IRCSock.cpp b/src/IRCSock.cpp
index 39d0e94e..511b183c 100644
--- a/src/IRCSock.cpp
+++ b/src/IRCSock.cpp
@@ -25,7 +25,7 @@ using std::set;
 using std::vector;
 using std::map;
 
-#define IRCSOCKMODULECALL(macFUNC, macEXITER) NETWORKMODULECALL(macFUNC, m_pNetwork->GetUser(), m_pNetwork, NULL, macEXITER)
+#define IRCSOCKMODULECALL(macFUNC, macEXITER) NETWORKMODULECALL(macFUNC, m_pNetwork->GetUser(), m_pNetwork, nullptr, macEXITER)
 // These are used in OnGeneralCTCP()
 const time_t CIRCSock::m_uCTCPFloodTime = 5;
 const unsigned int CIRCSock::m_uCTCPFloodCount = 5;
@@ -630,7 +630,7 @@ void CIRCSock::ReadLine(const CString& sData) {
 				CString sModeArg = sModes.Token(0);
 				bool bAdd = true;
 /* no module call defined (yet?)
-				MODULECALL(OnRawUserMode(*pOpNick, *this, sModeArg, sArgs), m_pNetwork->GetUser(), NULL, );
+				MODULECALL(OnRawUserMode(*pOpNick, *this, sModeArg, sArgs), m_pNetwork->GetUser(), nullptr, );
 */
 				for (unsigned int a = 0; a < sModeArg.size(); a++) {
 					const unsigned char& uMode = sModeArg[a];
diff --git a/src/Modules.cpp b/src/Modules.cpp
index 388bd02b..ce99e9e3 100644
--- a/src/Modules.cpp
+++ b/src/Modules.cpp
@@ -39,12 +39,12 @@ bool ZNC_NO_NEED_TO_DO_ANYTHING_ON_MODULE_CALL_EXITER;
 		try {                                                    \
 			CClient* pOldClient = pMod->GetClient();         \
 			pMod->SetClient(m_pClient);                      \
-			CUser* pOldUser = NULL;                      \
+			CUser* pOldUser = nullptr;                      \
 			if (m_pUser) {                               \
 				pOldUser = pMod->GetUser();              \
 				pMod->SetUser(m_pUser);                  \
 			}                                            \
-			CIRCNetwork* pNetwork = NULL;                \
+			CIRCNetwork* pNetwork = nullptr;                \
 			if (m_pNetwork) {                            \
 				pNetwork = pMod->GetNetwork();           \
 				pMod->SetNetwork(m_pNetwork);            \
@@ -70,12 +70,12 @@ bool ZNC_NO_NEED_TO_DO_ANYTHING_ON_MODULE_CALL_EXITER;
 			CModule::EModRet e = CModule::CONTINUE;          \
 			CClient* pOldClient = pMod->GetClient();         \
 			pMod->SetClient(m_pClient);                      \
-			CUser* pOldUser = NULL;                      \
+			CUser* pOldUser = nullptr;                      \
 			if (m_pUser) {                               \
 				pOldUser = pMod->GetUser();              \
 				pMod->SetUser(m_pUser);                  \
 			}                                            \
-			CIRCNetwork* pNetwork = NULL;                \
+			CIRCNetwork* pNetwork = nullptr;                \
 			if (m_pNetwork) {                            \
 				pNetwork = pMod->GetNetwork();           \
 				pMod->SetNetwork(m_pNetwork);            \
diff --git a/src/SSLVerifyHost.cpp b/src/SSLVerifyHost.cpp
index 2b5af5ef..a5830add 100644
--- a/src/SSLVerifyHost.cpp
+++ b/src/SSLVerifyHost.cpp
@@ -190,7 +190,7 @@ static int hostmatch(char *hostname, char *pattern)
     pattern[len-1]=0;
 
   pattern_wildcard = strchr(pattern, '*');
-  if(pattern_wildcard == NULL)
+  if(pattern_wildcard == nullptr)
     return Curl_raw_equal(pattern, hostname) ?
       CURL_HOST_MATCH : CURL_HOST_NOMATCH;
 
@@ -206,7 +206,7 @@ static int hostmatch(char *hostname, char *pattern)
      match. */
   wildcard_enabled = 1;
   pattern_label_end = strchr(pattern, '.');
-  if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
+  if(pattern_label_end == nullptr || strchr(pattern_label_end+1, '.') == nullptr ||
      pattern_wildcard > pattern_label_end ||
      Curl_raw_nequal(pattern, "xn--", 4)) {
     wildcard_enabled = 0;
@@ -216,7 +216,7 @@ static int hostmatch(char *hostname, char *pattern)
       CURL_HOST_MATCH : CURL_HOST_NOMATCH;
 
   hostname_label_end = strchr(hostname, '.');
-  if(hostname_label_end == NULL ||
+  if(hostname_label_end == nullptr ||
      !Curl_raw_equal(pattern_label_end, hostname_label_end))
     return CURL_HOST_NOMATCH;
 
@@ -303,9 +303,9 @@ typedef enum {
 */
 static HostnameValidationResult matches_common_name(const char *hostname, const X509 *server_cert) {
 	int common_name_loc = -1;
-	X509_NAME_ENTRY *common_name_entry = NULL;
-	ASN1_STRING *common_name_asn1 = NULL;
-	char *common_name_str = NULL;
+	X509_NAME_ENTRY *common_name_entry = nullptr;
+	ASN1_STRING *common_name_asn1 = nullptr;
+	char *common_name_str = nullptr;
 
 	// Find the position of the CN field in the Subject field of the certificate
 	common_name_loc = X509_NAME_get_index_by_NID(X509_get_subject_name((X509 *) server_cert), NID_commonName, -1);
@@ -315,13 +315,13 @@ static HostnameValidationResult matches_common_name(const char *hostname, const
 
 	// Extract the CN field
 	common_name_entry = X509_NAME_get_entry(X509_get_subject_name((X509 *) server_cert), common_name_loc);
-	if (common_name_entry == NULL) {
+	if (common_name_entry == nullptr) {
 		return Error;
 	}
 
 	// Convert the CN field to a C string
 	common_name_asn1 = X509_NAME_ENTRY_get_data(common_name_entry);
-	if (common_name_asn1 == NULL) {
+	if (common_name_asn1 == nullptr) {
 		return Error;
 	}			
 	common_name_str = (char *) ASN1_STRING_data(common_name_asn1);
@@ -354,11 +354,11 @@ static HostnameValidationResult matches_subject_alternative_name(const char *hos
 	HostnameValidationResult result = MatchNotFound;
 	int i;
 	int san_names_nb = -1;
-	STACK_OF(GENERAL_NAME) *san_names = NULL;
+	STACK_OF(GENERAL_NAME) *san_names = nullptr;
 
 	// Try to extract the names within the SAN extension from the certificate
-	san_names = reinterpret_cast<STACK_OF(GENERAL_NAME) *>(X509_get_ext_d2i((X509 *) server_cert, NID_subject_alt_name, NULL, NULL));
-	if (san_names == NULL) {
+	san_names = reinterpret_cast<STACK_OF(GENERAL_NAME) *>(X509_get_ext_d2i((X509 *) server_cert, NID_subject_alt_name, nullptr, nullptr));
+	if (san_names == nullptr) {
 		return NoSANPresent;
 	}
 	san_names_nb = sk_GENERAL_NAME_num(san_names);
@@ -405,7 +405,7 @@ static HostnameValidationResult matches_subject_alternative_name(const char *hos
 static HostnameValidationResult validate_hostname(const char *hostname, const X509 *server_cert) {
 	HostnameValidationResult result;
 
-	if((hostname == NULL) || (server_cert == NULL))
+	if((hostname == nullptr) || (server_cert == nullptr))
 		return Error;
 
 	// First try the Subject Alternative Names extension
diff --git a/src/Socket.cpp b/src/Socket.cpp
index 1c2e0a9a..6b838988 100644
--- a/src/Socket.cpp
+++ b/src/Socket.cpp
@@ -193,7 +193,7 @@ void CSockManager::CDNSJob::runMain() {
 	if (0 != this->iRes) {
 		DEBUG("Error in threaded DNS: " << gai_strerror(this->iRes));
 		if (this->aiResult) {
-			DEBUG("And aiResult is not NULL...");
+			DEBUG("And aiResult is not nullptr...");
 		}
 		this->aiResult = nullptr; // just for case. Maybe to call freeaddrinfo()?
 	}
@@ -413,7 +413,7 @@ CSocket::CSocket(CModule* pModule, const CString& sHostname, unsigned short uPor
 CSocket::~CSocket() {
 	CUser *pUser = nullptr;
 
-	// CWebSock could cause us to have a NULL pointer here
+	// CWebSock could cause us to have a nullptr pointer here
 	if (m_pModule) {
 		pUser = m_pModule->GetUser();
 		m_pModule->UnlinkSocket(this);
diff --git a/src/Utils.cpp b/src/Utils.cpp
index e7009c7b..a0602e93 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -51,23 +51,23 @@ constexpr const char* szDefaultDH2048 =
 	"-----END DH PARAMETERS-----\n";
 
 void CUtils::GenerateCert(FILE *pOut, const CString& sHost) {
-	EVP_PKEY *pKey = NULL;
-	X509 *pCert = NULL;
-	X509_NAME *pName = NULL;
+	EVP_PKEY *pKey = nullptr;
+	X509 *pCert = nullptr;
+	X509_NAME *pName = nullptr;
 	const int days = 365;
 	const int years = 10;
 
-	unsigned int uSeed = (unsigned int)time(NULL);
+	unsigned int uSeed = (unsigned int)time(nullptr);
 	int serial = (rand_r(&uSeed) % 9999);
 
-	RSA *pRSA = RSA_generate_key(2048, 0x10001, NULL, NULL);
+	RSA *pRSA = RSA_generate_key(2048, 0x10001, nullptr, nullptr);
 	if ((pKey = EVP_PKEY_new())) {
 		if (!EVP_PKEY_assign_RSA(pKey, pRSA)) {
 			EVP_PKEY_free(pKey);
 			return;
 		}
 
-		PEM_write_RSAPrivateKey(pOut, pRSA, NULL, NULL, 0, NULL, NULL);
+		PEM_write_RSAPrivateKey(pOut, pRSA, nullptr, nullptr, 0, nullptr, nullptr);
 
 		if (!(pCert = X509_new())) {
 			EVP_PKEY_free(pKey);
@@ -83,7 +83,7 @@ void CUtils::GenerateCert(FILE *pOut, const CString& sHost) {
 		pName = X509_get_subject_name(pCert);
 
 		const char *pLogName = getenv("LOGNAME");
-		const char *pHostName = NULL;
+		const char *pHostName = nullptr;
 
 		if (!sHost.empty()) {
 			pHostName = sHost.c_str();
@@ -502,7 +502,7 @@ SCString CUtils::GetEncodings() {
 			for (int st = 0; st < ucnv_countStandards(); ++st) {
 				const char* pStdName = ucnv_getStandard(st, e);
 				icu::LocalUEnumerationPointer ue(ucnv_openStandardNames(pConvName, pStdName, e));
-				while (const char* pStdConvNameEnum = uenum_next(ue.getAlias(), NULL, e)) {
+				while (const char* pStdConvNameEnum = uenum_next(ue.getAlias(), nullptr, e)) {
 					ssResult.insert(pStdConvNameEnum);
 				}
 			}
diff --git a/src/znc.cpp b/src/znc.cpp
index 15653bf8..c167b38a 100644
--- a/src/znc.cpp
+++ b/src/znc.cpp
@@ -1862,7 +1862,7 @@ public:
 	}
 	virtual ~CConnectQueueTimer() {
 		// This is only needed when ZNC shuts down:
-		// CZNC::~CZNC() sets its CConnectQueueTimer pointer to NULL and
+		// CZNC::~CZNC() sets its CConnectQueueTimer pointer to nullptr and
 		// calls the manager's Cleanup() which destroys all sockets and
 		// timers. If something calls CZNC::EnableConnectQueue() here
 		// (e.g. because a CIRCSock is destroyed), the socket manager
diff --git a/test/ThreadTest.cpp b/test/ThreadTest.cpp
index d95cbc19..4ba5f415 100644
--- a/test/ThreadTest.cpp
+++ b/test/ThreadTest.cpp
@@ -175,7 +175,7 @@ TEST(Thread, CancelJobWhenDone) {
 	fd_set fds;
 	FD_ZERO(&fds);
 	FD_SET(CThreadPool::Get().getReadFD(), &fds);
-	EXPECT_EQ(1, select(1 + CThreadPool::Get().getReadFD(), &fds, NULL, NULL, NULL));
+	EXPECT_EQ(1, select(1 + CThreadPool::Get().getReadFD(), &fds, nullptr, nullptr, nullptr));
 
 	// And only cancel it afterwards
 	CThreadPool::Get().cancelJob(pJob);