diff --git a/lib/base/filelogger.cpp b/lib/base/filelogger.cpp
index a0e61eca5..b15234f70 100644
--- a/lib/base/filelogger.cpp
+++ b/lib/base/filelogger.cpp
@@ -29,7 +29,7 @@ REGISTER_TYPE(FileLogger);
 
 REGISTER_STATSFUNCTION(FileLoggerStats, &FileLogger::StatsFunc);
 
-void FileLogger::StatsFunc(Dictionary::Ptr& status, Array::Ptr&)
+void FileLogger::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr&)
 {
 	Dictionary::Ptr nodes = new Dictionary();
 
diff --git a/lib/base/filelogger.hpp b/lib/base/filelogger.hpp
index 7557a3e03..cf2d342ec 100644
--- a/lib/base/filelogger.hpp
+++ b/lib/base/filelogger.hpp
@@ -37,7 +37,7 @@ public:
 	DECLARE_OBJECT(FileLogger);
 	DECLARE_OBJECTNAME(FileLogger);
 
-	static void StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata);
+	static void StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata);
 
 	virtual void Start(void);
 
diff --git a/lib/base/statsfunction.cpp b/lib/base/statsfunction.cpp
index 8b014e369..2fc565703 100644
--- a/lib/base/statsfunction.cpp
+++ b/lib/base/statsfunction.cpp
@@ -27,7 +27,7 @@ StatsFunction::StatsFunction(const Callback& function)
 	: m_Callback(function)
 { }
 
-void StatsFunction::Invoke(Dictionary::Ptr& status, Array::Ptr& perfdata)
+void StatsFunction::Invoke(const Dictionary::Ptr& status, const Array::Ptr& perfdata)
 {
 	m_Callback(status, perfdata);
 }
diff --git a/lib/base/statsfunction.hpp b/lib/base/statsfunction.hpp
index 687df0b61..cb9158b05 100644
--- a/lib/base/statsfunction.hpp
+++ b/lib/base/statsfunction.hpp
@@ -40,11 +40,11 @@ class I2_BASE_API StatsFunction : public Object
 public:
 	DECLARE_PTR_TYPEDEFS(StatsFunction);
 
-	typedef boost::function<void (Dictionary::Ptr& status, Array::Ptr& perfdata)> Callback;
+	typedef boost::function<void (const Dictionary::Ptr& status, const Array::Ptr& perfdata)> Callback;
 
 	StatsFunction(const Callback& function);
 
-	void Invoke(Dictionary::Ptr& status, Array::Ptr& perfdata);
+	void Invoke(const Dictionary::Ptr& status, const Array::Ptr& perfdata);
 
 private:
 	Callback m_Callback;
diff --git a/lib/base/sysloglogger.cpp b/lib/base/sysloglogger.cpp
index 4bafee799..f806cf6b0 100644
--- a/lib/base/sysloglogger.cpp
+++ b/lib/base/sysloglogger.cpp
@@ -28,7 +28,7 @@ REGISTER_TYPE(SyslogLogger);
 
 REGISTER_STATSFUNCTION(SyslogLoggerStats, &SyslogLogger::StatsFunc);
 
-void SyslogLogger::StatsFunc(Dictionary::Ptr& status, Array::Ptr&)
+void SyslogLogger::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr&)
 {
 	Dictionary::Ptr nodes = new Dictionary();
 
diff --git a/lib/base/sysloglogger.hpp b/lib/base/sysloglogger.hpp
index c7a9d55ac..3be5dcaed 100644
--- a/lib/base/sysloglogger.hpp
+++ b/lib/base/sysloglogger.hpp
@@ -38,7 +38,7 @@ public:
 	DECLARE_OBJECT(SyslogLogger);
 	DECLARE_OBJECTNAME(SyslogLogger);
 
-	static void StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata);
+	static void StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata);
 
 protected:
 	virtual void ProcessLogEntry(const LogEntry& entry);
diff --git a/lib/icinga/icingaapplication.cpp b/lib/icinga/icingaapplication.cpp
index 53eddc8f1..2a5edc8f7 100644
--- a/lib/icinga/icingaapplication.cpp
+++ b/lib/icinga/icingaapplication.cpp
@@ -63,7 +63,7 @@ void IcingaApplication::StaticInitialize(void)
 
 REGISTER_STATSFUNCTION(IcingaApplicationStats, &IcingaApplication::StatsFunc);
 
-void IcingaApplication::StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata)
+void IcingaApplication::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata)
 {
 	Dictionary::Ptr nodes = new Dictionary();
 
diff --git a/lib/icinga/icingaapplication.hpp b/lib/icinga/icingaapplication.hpp
index 2df3ecd3b..796a5c9c0 100644
--- a/lib/icinga/icingaapplication.hpp
+++ b/lib/icinga/icingaapplication.hpp
@@ -42,7 +42,7 @@ public:
 
 	int Main(void);
 
-	static void StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata);
+	static void StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata);
 
 	static IcingaApplication::Ptr GetInstance(void);
 
diff --git a/lib/icinga/icingastatuswriter.cpp b/lib/icinga/icingastatuswriter.cpp
index f1df5fdd6..105d6a180 100644
--- a/lib/icinga/icingastatuswriter.cpp
+++ b/lib/icinga/icingastatuswriter.cpp
@@ -35,7 +35,7 @@ REGISTER_TYPE(IcingaStatusWriter);
 
 REGISTER_STATSFUNCTION(IcingaStatusWriterStats, &IcingaStatusWriter::StatsFunc);
 
-void IcingaStatusWriter::StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata)
+void IcingaStatusWriter::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata)
 {
 	Dictionary::Ptr nodes = new Dictionary();
 
diff --git a/lib/icinga/icingastatuswriter.hpp b/lib/icinga/icingastatuswriter.hpp
index 3f2fe2d3e..80b4182cc 100644
--- a/lib/icinga/icingastatuswriter.hpp
+++ b/lib/icinga/icingastatuswriter.hpp
@@ -35,7 +35,7 @@ public:
 	DECLARE_OBJECT(IcingaStatusWriter);
 	DECLARE_OBJECTNAME(IcingaStatusWriter);
 
-	static void StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata);
+	static void StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata);
 	static Dictionary::Ptr GetStatusData(void);
 
 protected:
diff --git a/lib/remote/apilistener.cpp b/lib/remote/apilistener.cpp
index d7956eecb..2ccc763a9 100644
--- a/lib/remote/apilistener.cpp
+++ b/lib/remote/apilistener.cpp
@@ -747,7 +747,7 @@ void ApiListener::ReplayLog(const ApiClient::Ptr& client)
 	}
 }
 
-void ApiListener::StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata)
+void ApiListener::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata)
 {
 	Dictionary::Ptr nodes = new Dictionary();
 	std::pair<Dictionary::Ptr, Dictionary::Ptr> stats;
diff --git a/lib/remote/apilistener.hpp b/lib/remote/apilistener.hpp
index 884c1b034..122169eca 100644
--- a/lib/remote/apilistener.hpp
+++ b/lib/remote/apilistener.hpp
@@ -59,7 +59,7 @@ public:
 	void SyncSendMessage(const Endpoint::Ptr& endpoint, const Dictionary::Ptr& message);
 	void RelayMessage(const MessageOrigin& origin, const DynamicObject::Ptr& secobj, const Dictionary::Ptr& message, bool log);
 
-	static void StatsFunc(Dictionary::Ptr& status, Array::Ptr& perfdata);
+	static void StatsFunc(const Dictionary::Ptr& status, const Array::Ptr& perfdata);
 	std::pair<Dictionary::Ptr, Dictionary::Ptr> GetStatus(void);
 
 	void AddAnonymousClient(const ApiClient::Ptr& aclient);