diff --git a/src/chat/cpim/header/cpim-core-headers.cpp b/src/chat/cpim/header/cpim-core-headers.cpp
index 1a85d7e81..0da0b2721 100644
--- a/src/chat/cpim/header/cpim-core-headers.cpp
+++ b/src/chat/cpim/header/cpim-core-headers.cpp
@@ -17,6 +17,13 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
+#include <iomanip>
+#include <sstream>
+
+#include "linphone/utils/utils.h"
+
+#include "logger/logger.h"
+
 #include "chat/cpim/parser/cpim-parser.h"
 #include "cpim-header-p.h"
 
@@ -28,50 +35,348 @@ using namespace std;
 
 LINPHONE_BEGIN_NAMESPACE
 
-Cpim::CoreHeader::CoreHeader () : Header(*new HeaderPrivate) {}
+class Cpim::ContactHeaderPrivate : public HeaderPrivate {
+public:
+	string uri;
+	string formalName;
+};
 
-Cpim::CoreHeader::CoreHeader (HeaderPrivate &p) : Header(p) {}
+Cpim::ContactHeader::ContactHeader () : Header(*new ContactHeaderPrivate) {}
 
-Cpim::CoreHeader::~CoreHeader () {}
+Cpim::ContactHeader::ContactHeader (const string &uri, const string &formalName) : ContactHeader() {
+	setUri(uri);
+	setFormalName(formalName);
+}
 
-bool Cpim::CoreHeader::isValid () const {
-	return !getValue().empty();
+string Cpim::ContactHeader::getUri () const {
+	L_D();
+	return d->uri;
+}
+
+bool Cpim::ContactHeader::setUri (const string &uri) {
+	if (uri.empty())
+		return false;
+
+	L_D();
+	d->uri = uri;
+
+	return true;
+}
+
+string Cpim::ContactHeader::getFormalName () const {
+	L_D();
+	return d->formalName;
+}
+
+bool Cpim::ContactHeader::setFormalName (const string &formalName) {
+	if (formalName.empty())
+		return false;
+
+	L_D();
+	if (formalName.front() == '\"' && formalName.back() == '\"')
+		d->formalName = formalName.substr(1, formalName.size() - 2);
+	else if (formalName.back() == ' ')
+		d->formalName = formalName.substr(0, formalName.size() - 1);
+	else
+		d->formalName = formalName;
+
+	return true;
+}
+
+string Cpim::ContactHeader::getValue () const {
+	L_D();
+	return "\"" + d->formalName + "\"" + "<" + d->uri + ">";
+}
+
+string Cpim::ContactHeader::asString () const {
+	return getName() + ": " + getValue() + "\r\n";
 }
 
 // -----------------------------------------------------------------------------
 
-#define MAKE_CORE_HEADER_IMPL(CLASS_PREFIX) \
-	bool Cpim::CLASS_PREFIX ## Header::setValue(const string &value) { \
-		return Parser::getInstance()->coreHeaderIsValid<CLASS_PREFIX ## Header>(value) && Header::setValue(value); \
-	}
+class Cpim::MessageIdHeaderPrivate : public HeaderPrivate {
+public:
+	string token;
+};
 
-MAKE_CORE_HEADER_IMPL(From);
-MAKE_CORE_HEADER_IMPL(To);
-MAKE_CORE_HEADER_IMPL(Cc);
-MAKE_CORE_HEADER_IMPL(DateTime);
+Cpim::MessageIdHeader::MessageIdHeader () : Header(*new MessageIdHeaderPrivate) {}
 
-MAKE_CORE_HEADER_IMPL(Ns);
-MAKE_CORE_HEADER_IMPL(Require);
+Cpim::MessageIdHeader::MessageIdHeader (const string &token) : MessageIdHeader() {
+	L_D();
+	d->token = token;
+}
 
-#undef MAKE_CORE_HEADER_IMPL
+string Cpim::MessageIdHeader::getToken () const {
+	L_D();
+	return d->token;
+}
+
+bool Cpim::MessageIdHeader::setToken (string token) {
+	if (token.empty())
+		return false;
+
+	L_D();
+	d->token = token;
+
+	return true;
+}
+
+string Cpim::MessageIdHeader::getValue () const {
+	return getToken();
+}
+
+string Cpim::MessageIdHeader::asString () const {
+	return getName() + ": " + getValue() + "\r\n";
+}
 
 // -----------------------------------------------------------------------------
 
-void Cpim::CoreHeader::force (const string &value) {
-	Header::setValue(value);
+class Cpim::DateTimeHeaderPrivate : public HeaderPrivate {
+public:
+	tm timeT;
+	tm timeTOffset;
+	string signOffset;
+};
+
+Cpim::DateTimeHeader::DateTimeHeader () : Header(*new DateTimeHeaderPrivate) {}
+
+Cpim::DateTimeHeader::DateTimeHeader (time_t time) : DateTimeHeader() {
+	setTime(time);
+}
+
+Cpim::DateTimeHeader::DateTimeHeader (const tm &time, const tm &timeOffset, const string &signOffset) : DateTimeHeader() {
+	setTime(time, timeOffset, signOffset);
+}
+
+time_t Cpim::DateTimeHeader::getTime () const {
+	L_D();
+
+	tm result = d->timeT;
+	result.tm_year -= 1900;
+	result.tm_isdst = 0;
+
+	if (d->signOffset == "+") {
+		result.tm_hour += d->timeTOffset.tm_hour;
+		result.tm_min += d->timeTOffset.tm_min;
+
+		while (result.tm_min > 59) {
+			result.tm_hour++;
+			result.tm_min -= 60;
+		}
+	}
+	else if (d->signOffset == "-") {
+		result.tm_hour -= d->timeTOffset.tm_hour;
+		result.tm_hour -= d->timeTOffset.tm_min;
+
+		while (result.tm_min < 0) {
+			result.tm_hour--;
+			result.tm_min += 60;
+		}
+	}
+
+	return Utils::getTmAsTimeT(result);
+}
+
+bool Cpim::DateTimeHeader::setTime (const time_t time) {
+	L_D();
+
+	d->signOffset = "Z";
+	d->timeT = Utils::getTimeTAsTm(time);
+	d->timeT.tm_year += 1900;
+
+	return true;
+}
+
+bool Cpim::DateTimeHeader::setTime (const tm &time, const tm &timeOffset, const string &signOffset) {
+	L_D();
+
+	d->timeT = time;
+	d->timeTOffset = timeOffset;
+	d->signOffset = signOffset;
+
+	return true;
+}
+
+string Cpim::DateTimeHeader::getValue () const {
+ 	L_D();
+
+	stringstream ss;
+	ss << setfill('0') << setw(4) << d->timeT.tm_year << "-"
+		<< setfill('0') << setw(2) << d->timeT.tm_mon << "-"
+		<< setfill('0') << setw(2) << d->timeT.tm_mday << "T"
+		<< setfill('0') << setw(2) << d->timeT.tm_hour << ":"
+		<< setfill('0') << setw(2) << d->timeT.tm_min << ":"
+		<< setfill('0') << setw(2) << d->timeT.tm_sec;
+
+	ss << d->signOffset;
+	if (d->signOffset != "Z")
+		ss << setfill('0') << setw(2) << d->timeTOffset.tm_hour << ":"
+			<< setfill('0') << setw(2) << d->timeTOffset.tm_min;
+
+ 	return ss.str();
+}
+
+string Cpim::DateTimeHeader::asString () const {
+	return getName() + ": " + getValue() + "\r\n";
+}
+
+struct tm Cpim::DateTimeHeader::getTimeStruct () const {
+	L_D();
+	return d->timeT;
+}
+
+struct tm Cpim::DateTimeHeader::getTimeOffset () const {
+	L_D();
+	return d->timeTOffset;
+}
+
+string Cpim::DateTimeHeader::getSignOffset () const {
+	L_D();
+	return d->signOffset;
+}
+
+// -----------------------------------------------------------------------------
+
+class Cpim::NsHeaderPrivate : public HeaderPrivate {
+public:
+	string uri;
+	string prefixName;
+};
+
+Cpim::NsHeader::NsHeader () : Header(*new NsHeaderPrivate) {}
+
+Cpim::NsHeader::NsHeader (const string &uri, const string &prefixName) : NsHeader() {
+	L_D();
+	d->uri = uri;
+	d->prefixName = prefixName;
+}
+
+string Cpim::NsHeader::getUri () const {
+	L_D();
+	return d->uri;
+}
+
+bool Cpim::NsHeader::setUri (const string &uri) {
+	if (uri.empty())
+		return false;
+
+	L_D();
+	d->uri = uri;
+
+	return true;
+}
+
+string Cpim::NsHeader::getPrefixName () const {
+	L_D();
+	return d->prefixName;
+}
+
+bool Cpim::NsHeader::setPrefixName (const string &prefixName) {
+	if (prefixName.empty())
+		return false;
+
+	L_D();
+	d->prefixName = prefixName;
+
+	return true;
+}
+
+string Cpim::NsHeader::getValue () const {
+	L_D();
+
+	string ns;
+	if (!d->prefixName.empty())
+		ns = d->prefixName + " ";
+
+	return ns + "<" + d->uri + ">";
+}
+
+string Cpim::NsHeader::asString () const {
+	return getName() + ": " + getValue() + "\r\n";
+}
+
+// -----------------------------------------------------------------------------
+
+class Cpim::RequireHeaderPrivate : public HeaderPrivate {
+public:
+	list<string> headerNames;
+};
+
+Cpim::RequireHeader::RequireHeader () : Header(*new RequireHeaderPrivate) {}
+
+Cpim::RequireHeader::RequireHeader (const string &headerNames) : RequireHeader() {
+	L_D();
+	for (const string &header : Utils::split(headerNames, ",")) {
+		d->headerNames.push_back(header);
+	}
+}
+
+Cpim::RequireHeader::RequireHeader (const list<string> &headerNames) : RequireHeader() {
+	L_D();
+	d->headerNames = headerNames;
+}
+
+list<string> Cpim::RequireHeader::getHeaderNames () const {
+	L_D();
+	return d->headerNames;
+}
+
+bool Cpim::RequireHeader::addHeaderName (const string &headerName) {
+	if (headerName.empty())
+		return false;
+
+	L_D();
+	d->headerNames.push_back(headerName);
+
+	return true;
+}
+
+string Cpim::RequireHeader::getValue () const {
+	L_D();
+
+	string requires;
+	for (const string &header : d->headerNames) {
+		if (header != d->headerNames.front())
+			requires += ",";
+		requires += header;
+	}
+
+	return requires;
+}
+
+string Cpim::RequireHeader::asString () const {
+	return getName() + ": " + getValue() + "\r\n";
 }
 
 // -----------------------------------------------------------------------------
 
 class Cpim::SubjectHeaderPrivate : public HeaderPrivate {
 public:
+	string subject;
 	string language;
 };
 
-Cpim::SubjectHeader::SubjectHeader () : CoreHeader(*new SubjectHeaderPrivate) {}
+Cpim::SubjectHeader::SubjectHeader () : Header(*new SubjectHeaderPrivate) {}
 
-bool Cpim::SubjectHeader::setValue (const string &value) {
-	return Parser::getInstance()->coreHeaderIsValid<SubjectHeader>(value) && Header::setValue(value);
+Cpim::SubjectHeader::SubjectHeader (const string &subject, const string &language) : SubjectHeader() {
+	L_D();
+	d->subject = subject;
+	d->language = language;
+}
+
+string Cpim::SubjectHeader::getSubject () const {
+	L_D();
+	return d->subject;
+}
+
+bool Cpim::SubjectHeader::setSubject (const string &subject) {
+	if (subject.empty())
+		return false;
+
+	L_D();
+	d->subject = subject;
+
+	return true;
 }
 
 string Cpim::SubjectHeader::getLanguage () const {
@@ -80,7 +385,7 @@ string Cpim::SubjectHeader::getLanguage () const {
 }
 
 bool Cpim::SubjectHeader::setLanguage (const string &language) {
-	if (!language.empty() && !Parser::getInstance()->subjectHeaderLanguageIsValid(language))
+	if (!language.empty())
 		return false;
 
 	L_D();
@@ -89,20 +394,18 @@ bool Cpim::SubjectHeader::setLanguage (const string &language) {
 	return true;
 }
 
-string Cpim::SubjectHeader::asString () const {
+string Cpim::SubjectHeader::getValue () const {
 	L_D();
 
 	string languageParam;
 	if (!d->language.empty())
 		languageParam = ";lang=" + d->language;
 
-	return getName() + ":" + languageParam + " " + getValue() + "\r\n";
+	return languageParam + " " + d->subject;
 }
 
-void Cpim::SubjectHeader::force (const string &value, const string &language) {
-	L_D();
-	CoreHeader::force(value);
-	d->language = language;
+string Cpim::SubjectHeader::asString () const {
+	return getName() + ":" + getValue() + "\r\n";
 }
 
 LINPHONE_END_NAMESPACE
diff --git a/src/chat/cpim/header/cpim-core-headers.h b/src/chat/cpim/header/cpim-core-headers.h
index 1c7321ce4..89971cac0 100644
--- a/src/chat/cpim/header/cpim-core-headers.h
+++ b/src/chat/cpim/header/cpim-core-headers.h
@@ -20,60 +20,188 @@
 #ifndef _L_CPIM_CORE_HEADERS_H_
 #define _L_CPIM_CORE_HEADERS_H_
 
+#include <ctime>
+#include <list>
+
 #include "cpim-header.h"
 
 // =============================================================================
 
 LINPHONE_BEGIN_NAMESPACE
 
-#define MAKE_CORE_HEADER(CLASS_PREFIX, NAME) \
-	class LINPHONE_PUBLIC CLASS_PREFIX ## Header : public CoreHeader { \
+#define MAKE_CONTACT_HEADER(CLASS_PREFIX, NAME) \
+	class LINPHONE_PUBLIC CLASS_PREFIX ## Header : public ContactHeader { \
 	public: \
-		CLASS_PREFIX ## Header() = default; \
-		inline std::string getName() const override { \
+		CLASS_PREFIX ## Header () = default; \
+		CLASS_PREFIX ## Header (const std::string &uri, const std::string &formalName = "") : ContactHeader (uri, formalName) {} \
+		inline std::string getName () const override { \
 			return NAME; \
 		} \
-		bool setValue(const std::string &value) override; \
 	private: \
 		L_DISABLE_COPY(CLASS_PREFIX ## Header); \
 	};
 
 namespace Cpim {
-	class HeaderNode;
+	class DateTimeHeaderNode;
 
 	// -------------------------------------------------------------------------
-	// Generic core header.
+	// Specific Contact headers declaration.
 	// -------------------------------------------------------------------------
 
-	class LINPHONE_PUBLIC CoreHeader : public Header {
-		friend class HeaderNode;
+	class ContactHeaderPrivate;
 
+	class LINPHONE_PUBLIC ContactHeader : public Header {
 	public:
-		CoreHeader ();
+		ContactHeader ();
 
-		virtual ~CoreHeader () = 0;
+		ContactHeader (const std::string &uri, const std::string &formalName = "");
 
-		bool isValid () const override;
+		std::string getUri () const;
+		bool setUri (const std::string &uri);
 
-	protected:
-		explicit CoreHeader (HeaderPrivate &p);
+		std::string getFormalName () const;
+		bool setFormalName (const std::string &formalName);
 
-		void force (const std::string &value);
+		std::string getValue () const override;
+
+		std::string asString () const override;
 
 	private:
-		L_DISABLE_COPY(CoreHeader);
+		L_DECLARE_PRIVATE(ContactHeader);
+		L_DISABLE_COPY(ContactHeader);
 	};
 
 	// -------------------------------------------------------------------------
-	// Core headers.
+
+	MAKE_CONTACT_HEADER(From, "From");
+	MAKE_CONTACT_HEADER(To, "To");
+	MAKE_CONTACT_HEADER(Cc, "cc");
+
+	// -------------------------------------------------------------------------
+	// Specific MessageId declaration.
 	// -------------------------------------------------------------------------
 
-	MAKE_CORE_HEADER(From, "From");
-	MAKE_CORE_HEADER(To, "To");
-	MAKE_CORE_HEADER(Cc, "cc");
-	MAKE_CORE_HEADER(DateTime, "DateTime");
-	MAKE_CORE_HEADER(Ns, "NS");
-	MAKE_CORE_HEADER(Require, "Require");
+	class MessageIdHeaderPrivate;
+
+	class LINPHONE_PUBLIC MessageIdHeader : public Header {
+	public:
+		MessageIdHeader ();
+
+		MessageIdHeader (const std::string &token);
+
+		inline std::string getName() const override {
+			return "Message-ID";
+		}
+
+		std::string getToken () const;
+		bool setToken (std::string token);
+
+		std::string getValue () const override;
+
+		std::string asString () const override;
+
+	private:
+		L_DECLARE_PRIVATE(MessageIdHeader);
+		L_DISABLE_COPY(MessageIdHeader);
+	};
+
+	// -------------------------------------------------------------------------
+	// Specific DateTime declaration.
+	// -------------------------------------------------------------------------
+
+	class DateTimeHeaderPrivate;
+
+	class LINPHONE_PUBLIC DateTimeHeader : public Header {
+		friend class DateTimeHeaderNode;
+
+	public:
+		DateTimeHeader ();
+
+		DateTimeHeader (time_t time);
+
+		DateTimeHeader (const tm &time, const tm &timeOffset, const std::string &signOffset);
+
+		inline std::string getName () const override {
+			return "DateTime";
+		}
+
+		time_t getTime () const;
+		bool setTime (const time_t time);
+
+		bool setTime  (const tm &time, const tm &timeOffset, const std::string &signOffset);
+
+		std::string getValue () const override;
+
+		std::string asString () const override;
+
+	private:
+		tm getTimeStruct () const;
+		tm getTimeOffset () const;
+		std::string getSignOffset () const;
+
+		L_DECLARE_PRIVATE(DateTimeHeader);
+		L_DISABLE_COPY(DateTimeHeader);
+	};
+
+	// -------------------------------------------------------------------------
+	// Specific Ns declaration.
+	// -------------------------------------------------------------------------
+
+	class NsHeaderPrivate;
+
+	class LINPHONE_PUBLIC NsHeader : public Header {
+	public:
+		NsHeader ();
+
+		NsHeader (const std::string &uri, const std::string &prefixName = "");
+
+		inline std::string getName () const override {
+			return "NS";
+		}
+
+		std::string getPrefixName () const;
+		bool setPrefixName (const std::string &prefixName);
+
+		std::string getUri () const;
+		bool setUri (const std::string &uri);
+
+		std::string getValue () const override;
+
+		std::string asString () const override;
+
+	private:
+		L_DECLARE_PRIVATE(NsHeader);
+		L_DISABLE_COPY(NsHeader);
+	};
+
+	// -------------------------------------------------------------------------
+	// Specific Require declaration.
+	// -------------------------------------------------------------------------
+
+	class RequireHeaderPrivate;
+
+	class LINPHONE_PUBLIC RequireHeader : public Header {
+	public:
+		RequireHeader ();
+
+		RequireHeader (const std::string &headerNames);
+		RequireHeader (const std::list<std::string> &headerNames);
+
+		inline std::string getName () const override {
+			return "Require";
+		}
+
+		std::list<std::string> getHeaderNames () const;
+		bool addHeaderName (const std::string &headerName);
+
+		std::string getValue () const override;
+
+		std::string asString () const override;
+
+	private:
+		L_DECLARE_PRIVATE(RequireHeader);
+		L_DISABLE_COPY(RequireHeader);
+	};
 
 	// -------------------------------------------------------------------------
 	// Specific Subject declaration.
@@ -81,25 +209,25 @@ namespace Cpim {
 
 	class SubjectHeaderPrivate;
 
-	class LINPHONE_PUBLIC SubjectHeader : public CoreHeader {
-		friend class HeaderNode;
-
+	class LINPHONE_PUBLIC SubjectHeader : public Header {
 	public:
 		SubjectHeader ();
 
+		SubjectHeader (const std::string &subject, const std::string &language = "");
+
 		inline std::string getName () const override {
 			return "Subject";
 		}
 
-		bool setValue (const std::string &value) override;
+		std::string getSubject () const;
+		bool setSubject (const std::string &subject);
 
 		std::string getLanguage () const;
 		bool setLanguage (const std::string &language);
 
-		std::string asString () const override;
+		std::string getValue () const override;
 
-	protected:
-		void force (const std::string &value, const std::string &language);
+		std::string asString () const override;
 
 	private:
 		L_DECLARE_PRIVATE(SubjectHeader);
@@ -107,7 +235,7 @@ namespace Cpim {
 	};
 }
 
-#undef MAKE_CORE_HEADER
+#undef MAKE_CONTACT_HEADER
 
 LINPHONE_END_NAMESPACE
 
diff --git a/src/chat/cpim/header/cpim-generic-header.cpp b/src/chat/cpim/header/cpim-generic-header.cpp
index 67a7b81d4..8e4bc57ab 100644
--- a/src/chat/cpim/header/cpim-generic-header.cpp
+++ b/src/chat/cpim/header/cpim-generic-header.cpp
@@ -37,11 +37,24 @@ public:
 	GenericHeaderPrivate () : parameters(make_shared<list<pair<string, string> > >()) {}
 
 	string name;
+	string value;
 	shared_ptr<list<pair<string, string> > > parameters;
 };
 
 Cpim::GenericHeader::GenericHeader () : Header(*new GenericHeaderPrivate) {}
 
+Cpim::GenericHeader::GenericHeader (string name, string value, string parameters) : GenericHeader() {
+	L_D();
+	d->name = name;
+	d->value = value;
+
+	for (const auto &parameter : Utils::split(parameters, ';')) {
+		size_t equalIndex = parameter.find('=');
+		if (equalIndex != string::npos)
+			d->parameters->push_back(make_pair(parameter.substr(0, equalIndex), parameter.substr(equalIndex + 1)));
+	}
+}
+
 string Cpim::GenericHeader::getName () const {
 	L_D();
 	return d->name;
@@ -54,18 +67,26 @@ bool Cpim::GenericHeader::setName (const string &name) {
 		"From", "To", "cc", "DateTime", "Subject", "NS", "Require"
 	};
 
-	if (
-		reserved.find(name) != reserved.end() ||
-		!Parser::getInstance()->headerNameIsValid(name)
-	)
+	if (reserved.find(name) != reserved.end())
 		return false;
 
 	d->name = name;
 	return true;
 }
 
+string Cpim::GenericHeader::getValue () const {
+	L_D();
+	return d->value;
+}
+
 bool Cpim::GenericHeader::setValue (const string &value) {
-	return Parser::getInstance()->headerValueIsValid(value) && Header::setValue(value);
+	if (value.empty())
+		return false;
+
+	L_D();
+	d->value = value;
+
+	return true;
 }
 
 Cpim::GenericHeader::ParameterList Cpim::GenericHeader::getParameters () const {
@@ -75,10 +96,6 @@ Cpim::GenericHeader::ParameterList Cpim::GenericHeader::getParameters () const {
 
 bool Cpim::GenericHeader::addParameter (const string &key, const string &value) {
 	L_D();
-
-	if (!Parser::getInstance()->headerParameterIsValid(key + "=" + value))
-		return false;
-
 	d->parameters->push_back(make_pair(key, value));
 	return true;
 }
@@ -88,11 +105,6 @@ void Cpim::GenericHeader::removeParameter (const string &key, const string &valu
 	d->parameters->remove(make_pair(key, value));
 }
 
-bool Cpim::GenericHeader::isValid () const {
-	L_D();
-	return !d->name.empty() && !getValue().empty();
-}
-
 string Cpim::GenericHeader::asString () const {
 	L_D();
 
@@ -103,21 +115,4 @@ string Cpim::GenericHeader::asString () const {
 	return d->name + ":" + parameters + " " + getValue() + "\r\n";
 }
 
-// -----------------------------------------------------------------------------
-
-void Cpim::GenericHeader::force (const string &name, const string &value, const string &parameters) {
-	L_D();
-
-	// Set name/value.
-	d->name = name;
-	Header::setValue(value);
-
-	// Parse and build parameters list.
-	for (const auto &parameter : Utils::split(parameters, ';')) {
-		size_t equalIndex = parameter.find('=');
-		if (equalIndex != string::npos)
-			d->parameters->push_back(make_pair(parameter.substr(0, equalIndex), parameter.substr(equalIndex + 1)));
-	}
-}
-
 LINPHONE_END_NAMESPACE
diff --git a/src/chat/cpim/header/cpim-generic-header.h b/src/chat/cpim/header/cpim-generic-header.h
index 2433a9cb7..711b3c641 100644
--- a/src/chat/cpim/header/cpim-generic-header.h
+++ b/src/chat/cpim/header/cpim-generic-header.h
@@ -38,10 +38,13 @@ namespace Cpim {
 	public:
 		GenericHeader ();
 
+		GenericHeader (std::string name, std::string value, std::string parameters = "");
+
 		std::string getName () const override;
 		bool setName (const std::string &name);
 
-		bool setValue (const std::string &value) override;
+		std::string getValue () const override;
+		bool setValue (const std::string &value);
 
 		typedef std::shared_ptr<const std::list<std::pair<std::string, std::string> > > ParameterList;
 
@@ -49,13 +52,8 @@ namespace Cpim {
 		bool addParameter (const std::string &key, const std::string &value);
 		void removeParameter (const std::string &key, const std::string &value);
 
-		bool isValid () const override;
-
 		std::string asString () const override;
 
-	protected:
-		void force (const std::string &name, const std::string &value, const std::string &parameters);
-
 	private:
 		L_DECLARE_PRIVATE(GenericHeader);
 		L_DISABLE_COPY(GenericHeader);
diff --git a/src/chat/cpim/header/cpim-header-p.h b/src/chat/cpim/header/cpim-header-p.h
index 048e91309..2aaea0acb 100644
--- a/src/chat/cpim/header/cpim-header-p.h
+++ b/src/chat/cpim/header/cpim-header-p.h
@@ -30,8 +30,6 @@ LINPHONE_BEGIN_NAMESPACE
 namespace Cpim {
 	class HeaderPrivate : public ObjectPrivate {
 	private:
-		std::string value;
-
 		L_DECLARE_PUBLIC(Header);
 	};
 }
diff --git a/src/chat/cpim/header/cpim-header.cpp b/src/chat/cpim/header/cpim-header.cpp
index 8141d7811..6a3b83470 100644
--- a/src/chat/cpim/header/cpim-header.cpp
+++ b/src/chat/cpim/header/cpim-header.cpp
@@ -29,20 +29,4 @@ LINPHONE_BEGIN_NAMESPACE
 
 Cpim::Header::Header (HeaderPrivate &p) : Object(p) {}
 
-string Cpim::Header::getValue () const {
-	L_D();
-	return d->value;
-}
-
-bool Cpim::Header::setValue (const string &value) {
-	L_D();
-	d->value = value;
-	return true;
-}
-
-string Cpim::Header::asString () const {
-	L_D();
-	return getName() + ": " + d->value + "\r\n";
-}
-
 LINPHONE_END_NAMESPACE
diff --git a/src/chat/cpim/header/cpim-header.h b/src/chat/cpim/header/cpim-header.h
index 13dcfdce8..f71d115b0 100644
--- a/src/chat/cpim/header/cpim-header.h
+++ b/src/chat/cpim/header/cpim-header.h
@@ -35,12 +35,9 @@ namespace Cpim {
 
 		virtual std::string getName () const = 0;
 
-		std::string getValue () const;
-		virtual bool setValue (const std::string &value);
+		virtual std::string getValue () const = 0;
 
-		virtual bool isValid () const = 0;
-
-		virtual std::string asString () const;
+		virtual std::string asString () const = 0;
 
 	protected:
 		explicit Header (HeaderPrivate &p);