diff --git a/bacnet-stack/demo/object/msi.c b/bacnet-stack/demo/object/msi.c
index 15f77f7e..38728caa 100644
--- a/bacnet-stack/demo/object/msi.c
+++ b/bacnet-stack/demo/object/msi.c
@@ -67,6 +67,7 @@ static const int Properties_Required[] = {
 
 static const int Properties_Optional[] = {
     PROP_DESCRIPTION,
+    PROP_STATE_TEXT,
     -1
 };
 
@@ -399,7 +400,7 @@ int Multistate_Input_Encode_Property_APDU(
                     characterstring_init_ansi(&char_string,
                         Multistate_Input_State_Text(object_instance, i));
                     /* FIXME: this might go beyond MAX_APDU length! */
-                    apdu_len = encode_application_character_string(
+                    len = encode_application_character_string(
                         &apdu[apdu_len], 
                         &char_string);
                     /* add it if we have room */
diff --git a/bacnet-stack/include/ao.h b/bacnet-stack/include/ao.h
index 1dd638cd..5bb7f5bf 100644
--- a/bacnet-stack/include/ao.h
+++ b/bacnet-stack/include/ao.h
@@ -45,8 +45,11 @@ extern "C" {
         void);
     uint32_t Analog_Output_Index_To_Instance(
         unsigned index);
-    char *Analog_Output_Name(
-        uint32_t object_instance);
+    unsigned Analog_Output_Instance_To_Index(
+        uint32_t instance);
+    bool Analog_Output_Object_Instance_Add(
+        uint32_t instance);
+
     float Analog_Output_Present_Value(
         uint32_t object_instance);
     unsigned Analog_Output_Present_Value_Priority(
@@ -58,6 +61,18 @@ extern "C" {
     bool Analog_Output_Present_Value_Relinquish(
         uint32_t object_instance,
         unsigned priority);
+
+    char *Analog_Output_Name(
+        uint32_t object_instance);
+    bool Analog_Output_Name_Set(
+        uint32_t object_instance,
+        char *new_name);
+
+    char *Analog_Output_Description(
+        uint32_t instance);
+    bool Analog_Output_Description_Set(
+        uint32_t instance,
+        char *new_name);
     
     void Analog_Output_Init(void);
 
diff --git a/bacnet-stack/include/msi.h b/bacnet-stack/include/msi.h
index 69a4f557..06da4fa0 100644
--- a/bacnet-stack/include/msi.h
+++ b/bacnet-stack/include/msi.h
@@ -39,14 +39,15 @@ extern "C" {
         const int **pRequired,
         const int **pOptional,
         const int **pProprietary);
+    
     bool Multistate_Input_Valid_Instance(
         uint32_t object_instance);
     unsigned Multistate_Input_Count(
         void);
     uint32_t Multistate_Input_Index_To_Instance(
         unsigned index);
-    char *Multistate_Input_Name(
-        uint32_t object_instance);
+    unsigned Multistate_Input_Instance_To_Index(
+        uint32_t instance);    
 
     int Multistate_Input_Encode_Property_APDU(
         uint8_t * apdu,
@@ -61,18 +62,29 @@ extern "C" {
         BACNET_ERROR_CLASS * error_class,
         BACNET_ERROR_CODE * error_code);
 
+    /* optional API */
+    bool Multistate_Input_Object_Instance_Add(
+        uint32_t instance);
+    char *Multistate_Input_Name(
+        uint32_t object_instance);
+    bool Multistate_Input_Name_Set(
+        uint32_t object_instance,
+        char *new_name);
+    uint32_t Multistate_Input_Present_Value(
+        uint32_t object_instance);
     bool Multistate_Input_Present_Value_Set(
         uint32_t object_instance,
         uint32_t value);
-
     bool Multistate_Input_Description_Set(
         uint32_t object_instance,
         char *text_string);
-
     bool Multistate_Input_State_Text_Set(
         uint32_t object_instance,
         uint32_t state_index,
         char *new_name);
+    bool Multistate_Input_Max_States_Set(
+        uint32_t instance,
+        uint32_t max_states_requested);
 
     void Multistate_Input_Init(
         void);