diff --git a/headers/private/app/RegistrarDefs.h b/headers/private/app/RegistrarDefs.h
index b793e7ca69..2087fdf912 100644
--- a/headers/private/app/RegistrarDefs.h
+++ b/headers/private/app/RegistrarDefs.h
@@ -30,12 +30,15 @@
 #include <Errors.h>
 #include <Roster.h>
 
+namespace BPrivate {
+
 // names
 extern const char *kRegistrarSignature;
 extern const char *kRosterThreadName;
-extern const char *kRosterPortName;
 extern const char *kRAppLooperPortName;
 
+extern const char *get_roster_port_name();
+
 // message constants
 enum {
 	// replies
@@ -159,5 +162,7 @@ struct flat_app_info {
 	char		ref_name[B_FILE_NAME_LENGTH + 1];
 };
 
+}	// namespace BPrivate
+
 #endif	// REGISTRAR_DEFS_H
 
diff --git a/src/kits/app/RegistrarDefs.cpp b/src/kits/app/RegistrarDefs.cpp
index 1ef1aacf41..5481febfe5 100644
--- a/src/kits/app/RegistrarDefs.cpp
+++ b/src/kits/app/RegistrarDefs.cpp
@@ -24,11 +24,25 @@
 //	Description:	API classes - registrar interface.
 //------------------------------------------------------------------------------
 
+#include <AppMisc.h>
 #include <RegistrarDefs.h>
 
+namespace BPrivate {
+
 // names
-const char *kRegistrarSignature	= "application/x-vnd.OBOS-Registrar";
-const char *kRosterThreadName	= "_obos_roster_thread_";
-const char *kRosterPortName		= "_obos_roster_port_";
+const char *kRegistrarSignature	= "application/x-vnd.haiku-registrar";
+const char *kRosterThreadName	= "_roster_thread_";
 const char *kRAppLooperPortName	= "rAppLooperPort";
 
+// get_roster_port_name
+/*!	\brief Returns the name of the main request port of the registrar (roster).
+	\return the name of the registrar request port.
+*/
+const char *
+get_roster_port_name()
+{
+	return (BPrivate::is_running_on_haiku()
+		? "_roster_port_" : "_obos_roster_port_");
+}
+
+}	// namespace BPrivate