diff --git a/Modules.cpp b/Modules.cpp
index a45a2537..a5ec25e7 100644
--- a/Modules.cpp
+++ b/Modules.cpp
@@ -144,14 +144,14 @@ CModule::~CModule() {
 
 void CModule::SetUser(CUser* pUser) { m_pUser = pUser; }
 void CModule::SetClient(CClient* pClient) { m_pClient = pClient; }
-void CModule::Unload() { throw UNLOAD; }
+void CModule::Unload() const { throw UNLOAD; }
 
 bool CModule::LoadRegistry() {
 	//CString sPrefix = (m_pUser) ? m_pUser->GetUserName() : ".global";
 	return (m_mssRegistry.ReadFromDisk(GetSavePath() + "/.registry", 0600) == MCString::MCS_SUCCESS);
 }
 
-bool CModule::SaveRegistry() {
+bool CModule::SaveRegistry() const {
 	//CString sPrefix = (m_pUser) ? m_pUser->GetUserName() : ".global";
 	return (m_mssRegistry.WriteToDisk(GetSavePath() + "/.registry", 0600) == MCString::MCS_SUCCESS);
 }
@@ -165,8 +165,8 @@ bool CModule::SetNV(const CString & sName, const CString & sValue, bool bWriteTo
 	return true;
 }
 
-CString CModule::GetNV(const CString & sName) {
-	MCString::iterator it = m_mssRegistry.find(sName);
+CString CModule::GetNV(const CString & sName) const {
+	MCString::const_iterator it = m_mssRegistry.find(sName);
 
 	if (it != m_mssRegistry.end()) {
 		return it->second;
@@ -247,7 +247,7 @@ bool CModule::UnlinkTimer(CTimer* pTimer) {
 	return false;
 }
 
-CTimer* CModule::FindTimer(const CString& sLabel) {
+CTimer* CModule::FindTimer(const CString& sLabel) const {
 	set<CTimer*>::iterator it;
 	for (it = m_sTimers.begin(); it != m_sTimers.end(); ++it) {
 		CTimer* pTimer = *it;
@@ -335,7 +335,7 @@ bool CModule::UnlinkSocket(CSocket* pSocket) {
 	return false;
 }
 
-CSocket* CModule::FindSocket(const CString& sSockName) {
+CSocket* CModule::FindSocket(const CString& sSockName) const {
 	set<CSocket*>::iterator it;
 	for (it = m_sSockets.begin(); it != m_sSockets.end(); ++it) {
 		CSocket* pSocket = *it;
@@ -456,7 +456,7 @@ CModule::EModRet CModule::OnChanNotice(CNick& Nick, CChan& Channel, CString& sMe
 CModule::EModRet CModule::OnTopic(CNick& Nick, CChan& Channel, CString& sTopic) { return CONTINUE; }
 CModule::EModRet CModule::OnTimerAutoJoin(CChan& Channel) { return CONTINUE; }
 
-ModHandle CModule::GetDLL() { return m_pDLL; }
+ModHandle CModule::GetDLL() const { return m_pDLL; }
 bool CModule::PutIRC(const CString& sLine) {
 	return (m_pUser) ? m_pUser->PutIRC(sLine) : false;
 }
diff --git a/Modules.h b/Modules.h
index e261c80e..49c1caa3 100644
--- a/Modules.h
+++ b/Modules.h
@@ -255,7 +255,7 @@ public:
 
 	/** This function throws CModule::UNLOAD which causes this module to be unloaded.
 	 */
-	void Unload();
+	void Unload() const;
 
 	/** This module hook is called when a module is loaded
 	 *  @param sArgsi The arguments for the modules.
@@ -645,7 +645,7 @@ public:
 	 */
 	virtual EModRet OnTimerAutoJoin(CChan& Channel);
 
-	ModHandle GetDLL();
+	ModHandle GetDLL() const;
 	static double GetCoreVersion() { return VERSION; }
 
 	/** This function sends a given raw IRC line to the IRC server, if we
@@ -716,7 +716,7 @@ public:
 	bool RemTimer(CTimer* pTimer);
 	bool RemTimer(const CString& sLabel);
 	bool UnlinkTimer(CTimer* pTimer);
-	CTimer* FindTimer(const CString& sLabel);
+	CTimer* FindTimer(const CString& sLabel) const;
 	set<CTimer*>::const_iterator BeginTimers() const { return m_sTimers.begin(); }
 	set<CTimer*>::const_iterator EndTimers() const { return m_sTimers.end(); }
 	virtual void ListTimers();
@@ -727,16 +727,16 @@ public:
 	bool RemSocket(CSocket* pSocket);
 	bool RemSocket(const CString& sSockName);
 	bool UnlinkSocket(CSocket* pSocket);
-	CSocket* FindSocket(const CString& sSockName);
+	CSocket* FindSocket(const CString& sSockName) const;
 	set<CSocket*>::const_iterator BeginSockets() const { return m_sSockets.begin(); }
 	set<CSocket*>::const_iterator EndSockets() const { return m_sSockets.end(); }
 	virtual void ListSockets();
 	// !Socket stuff
 
 	bool LoadRegistry();
-	bool SaveRegistry();
+	bool SaveRegistry() const;
 	bool SetNV(const CString & sName, const CString & sValue, bool bWriteToDisk = true);
-	CString GetNV(const CString & sName);
+	CString GetNV(const CString & sName) const;
 	bool DelNV(const CString & sName, bool bWriteToDisk = true);
 	MCString::iterator FindNV(const CString & sName) { return m_mssRegistry.find(sName); }
 	MCString::iterator EndNV() { return m_mssRegistry.end(); }
@@ -764,12 +764,12 @@ public:
 	 *           except when we are in a user-specific module hook in which
 	 *           case this is the user pointer.
 	 */
-	CUser* GetUser() { return m_pUser; }
+	CUser* GetUser() const { return m_pUser; }
 	/** @returns NULL except when we are in a client-specific module hook in
 	 *           which case this is the client for which the hook is called.
 	 */
-	CClient* GetClient() { return m_pClient; }
-	CSockManager* GetManager() { return m_pManager; }
+	CClient* GetClient() const { return m_pClient; }
+	CSockManager* GetManager() const { return m_pManager; }
 	// !Getters
 
 protected:
diff --git a/User.cpp b/User.cpp
index 0d5239a4..d97006a6 100644
--- a/User.cpp
+++ b/User.cpp
@@ -602,7 +602,7 @@ bool CUser::DelChan(const CString& sName) {
 	return false;
 }
 
-bool CUser::PrintLine(CFile& File, CString sName, CString sValue) {
+bool CUser::PrintLine(CFile& File, CString sName, CString sValue) const {
 	sName.Trim();
 	sValue.Trim();
 
@@ -674,7 +674,7 @@ bool CUser::WriteConfig(CFile& File) {
 
 	// CTCP Replies
 	if (!m_mssCTCPReplies.empty()) {
-		for (MCString::iterator itb = m_mssCTCPReplies.begin(); itb != m_mssCTCPReplies.end(); ++itb) {
+		for (MCString::const_iterator itb = m_mssCTCPReplies.begin(); itb != m_mssCTCPReplies.end(); ++itb) {
 			PrintLine(File, "CTCPReply", itb->first.AsUpper() + " " + itb->second);
 		}
 
@@ -1177,7 +1177,7 @@ bool CUser::SetBufferCount(unsigned int u, bool bForce) {
 	return true;
 }
 
-void CUser::CheckIRCConnect() {
+void CUser::CheckIRCConnect() const {
 	// Do we want to connect?
 	if (m_bIRCConnectEnabled && GetIRCSock() == NULL)
 		CZNC::Get().EnableConnectUser();
diff --git a/User.h b/User.h
index fe1628d4..6a621e13 100644
--- a/User.h
+++ b/User.h
@@ -46,7 +46,7 @@ public:
 		return CUtils::SaltedSHA256Hash(sPass, sSalt);
 	}
 
-	bool PrintLine(CFile& File, CString sName, CString sValue);
+	bool PrintLine(CFile& File, CString sName, CString sValue) const;
 	bool WriteConfig(CFile& File);
 	CChan* FindChan(const CString& sName) const;
 	bool AddChan(CChan* pChan);
@@ -111,7 +111,7 @@ public:
 	bool IsIRCConnected() const { return GetIRCSock() != NULL; }
 	void IRCConnected(CIRCSock* pIRCSock);
 	void IRCDisconnected();
-	void CheckIRCConnect();
+	void CheckIRCConnect() const;
 
 	void AddDCCBounce(CDCCBounce* p) { m_sDCCBounces.insert(p); }
 	void DelDCCBounce(CDCCBounce* p) { m_sDCCBounces.erase(p); }
@@ -220,7 +220,7 @@ public:
 	unsigned long long BytesWritten() const { return m_uBytesWritten; }
 	unsigned int JoinTries() const { return m_uMaxJoinTries; }
 	unsigned int MaxJoins() const { return m_uMaxJoins; }
-	bool IsIRCAway() { return m_bIRCAway; }
+	bool IsIRCAway() const { return m_bIRCAway; }
 	CString GetSkinName() const;
 	// !Getters
 private:
diff --git a/ZNCString.cpp b/ZNCString.cpp
index 7dcab833..50c16065 100644
--- a/ZNCString.cpp
+++ b/ZNCString.cpp
@@ -805,13 +805,13 @@ CString CString::SHA256() const {
 }
 
 #ifdef HAVE_LIBSSL
-CString CString::Encrypt_n(const CString& sPass, const CString& sIvec) {
+CString CString::Encrypt_n(const CString& sPass, const CString& sIvec) const {
 	CString sRet;
 	sRet.Encrypt(sPass, sIvec);
 	return sRet;
 }
 
-CString CString::Decrypt_n(const CString& sPass, const CString& sIvec) {
+CString CString::Decrypt_n(const CString& sPass, const CString& sIvec) const {
 	CString sRet;
 	sRet.Decrypt(sPass, sIvec);
 	return sRet;
@@ -1031,7 +1031,7 @@ bool CString::RightChomp(unsigned int uLen) {
 }
 
 //////////////// MCString ////////////////
-int MCString::WriteToDisk(const CString& sPath, mode_t iMode) {
+int MCString::WriteToDisk(const CString& sPath, mode_t iMode) const {
 	CFile cFile(sPath);
 
 	if (this->empty()) {
@@ -1045,7 +1045,7 @@ int MCString::WriteToDisk(const CString& sPath, mode_t iMode) {
 		return MCS_EOPEN;
 	}
 
-	for (MCString::iterator it = this->begin(); it != this->end(); ++it) {
+	for (MCString::const_iterator it = this->begin(); it != this->end(); ++it) {
 		CString sKey = it->first;
 		CString sValue = it->second;
 		if (!WriteFilter(sKey, sValue)) {
@@ -1095,7 +1095,7 @@ int MCString::ReadFromDisk(const CString& sPath, mode_t iMode) {
 
 static const char hexdigits[] = "0123456789abcdef";
 
-CString& MCString::Encode(CString& sValue) {
+CString& MCString::Encode(CString& sValue) const {
 	CString sTmp;
 	for (CString::iterator it = sValue.begin(); it != sValue.end(); ++it) {
 		if (isalnum(*it)) {
@@ -1111,7 +1111,7 @@ CString& MCString::Encode(CString& sValue) {
 	return sValue;
 }
 
-CString& MCString::Decode(CString& sValue) {
+CString& MCString::Decode(CString& sValue) const {
 	const char *pTmp = sValue.c_str();
 	char *endptr;
 	CString sTmp;
diff --git a/ZNCString.h b/ZNCString.h
index 3ced8428..ecb6a3f7 100644
--- a/ZNCString.h
+++ b/ZNCString.h
@@ -141,8 +141,8 @@ public:
 	CString Base64Encode_n(unsigned int uWrap = 0) const;
 
 #ifdef HAVE_LIBSSL
-	CString Encrypt_n(const CString& sPass, const CString& sIvec = "");
-	CString Decrypt_n(const CString& sPass, const CString& sIvec = "");
+	CString Encrypt_n(const CString& sPass, const CString& sIvec = "") const;
+	CString Decrypt_n(const CString& sPass, const CString& sIvec = "") const;
 	void Encrypt(const CString& sPass, const CString& sIvec = "");
 	void Decrypt(const CString& sPass, const CString& sIvec = "");
 	void Crypt(const CString& sPass, bool bEncrypt, const CString& sIvec = "");
@@ -198,15 +198,15 @@ public:
 		MCS_EREADFIL  = 4
 	};
 
-	int WriteToDisk(const CString& sPath, mode_t iMode = 0644);
+	int WriteToDisk(const CString& sPath, mode_t iMode = 0644) const;
 	int ReadFromDisk(const CString& sPath, mode_t iMode = 0644);
 
-	virtual bool WriteFilter(CString& sKey, CString& sValue) { return true; }
-	virtual bool ReadFilter(CString& sKey, CString& sValue) { return true; }
+	virtual bool WriteFilter(CString& sKey, CString& sValue) const { return true; }
+	virtual bool ReadFilter(CString& sKey, CString& sValue) const { return true; }
 
 	//! make them parse safe, right now using hex encoding on anything !isalnum
-	virtual CString& Encode(CString& sValue);
-	virtual CString& Decode(CString& sValue);
+	virtual CString& Encode(CString& sValue) const;
+	virtual CString& Decode(CString& sValue) const;
 };
 
 #endif // !ZNCSTRING_H