diff --git a/src/mms/inc/mms_value.h b/src/mms/inc/mms_value.h
index b4222f04..e67bccb2 100644
--- a/src/mms/inc/mms_value.h
+++ b/src/mms/inc/mms_value.h
@@ -554,6 +554,21 @@ MmsValue_getBinaryTimeAsUtcMs(const MmsValue* self);
 LIB61850_API void
 MmsValue_setOctetString(MmsValue* self, const uint8_t* buf, int size);
 
+/**
+ * \brief Set a single octet of an MmsValue object of type MMS_OCTET_STRING.
+ *
+ * This method will copy the provided octet to the internal buffer of the
+ * MmsValue instance, at the 'octetPos' position. This will only happen
+ * if the internal buffer size is large enough. Otherwise the object value is not changed.
+ *
+ * \param self MmsValue instance to operate on. Has to be of a type MMS_OCTET_STRING.
+ * \param octetPos the position of the octet in the octet string. Starting with 0.
+ *        The octet with position 0 is the first octet if the MmsValue instance is serialized.
+ * \param value the new value of the octet (0 to 255, or 0x00 to 0xFF)
+ */
+LIB61850_API void
+MmsValue_setOctetStringOctet(MmsValue* self, int octetPos, uint8_t value);
+
 /**
  * \brief Returns the size in bytes of an MmsValue object of type MMS_OCTET_STRING.
  *
@@ -592,6 +607,20 @@ MmsValue_getOctetStringMaxSize(MmsValue* self);
 LIB61850_API uint8_t*
 MmsValue_getOctetStringBuffer(MmsValue* self);
 
+/**
+ * \brief Get the value of a single octet of an MmsType object of type MMS_OCTET_STRING
+ *
+ * NOTE: The octet quantity of the octet string can be requested with
+ * the \ref MmsValue_getOctetStringSize function.
+ *
+ * \param self MmsValue instance to operate on. Has to be of a type MMS_OCTET_STRING.
+ * \param octetPos the position of the octet in the octet string. Starting with 0. The octet
+ *        with position 0 is the first octet if the MmsValue instance is serialized.
+ * \return the value of the octet (0 to 255, or 0x00 to 0xFF)
+ */
+LIB61850_API uint8_t
+MmsValue_getOctetStringOctet(MmsValue* self, int octetPos);
+
 /**
  * \brief Update the value of an MmsValue instance by the value of another MmsValue instance.
  *
diff --git a/src/mms/iso_mms/common/mms_value.c b/src/mms/iso_mms/common/mms_value.c
index b6538262..0da7a196 100644
--- a/src/mms/iso_mms/common/mms_value.c
+++ b/src/mms/iso_mms/common/mms_value.c
@@ -1426,6 +1426,18 @@ MmsValue_setOctetString(MmsValue* self, const uint8_t* buf, int size)
     }
 }
 
+void
+MmsValue_setOctetStringOctet(MmsValue* self, int octetPos, uint8_t value)
+{
+    if (octetPos < self->value.octetString.maxSize) {
+        self->value.octetString.buf[octetPos] = value;
+
+        if (octetPos >= self->value.octetString.size) {
+            self->value.octetString.size = octetPos + 1;
+        }
+    }
+}
+
 uint16_t
 MmsValue_getOctetStringSize(const MmsValue* self)
 {
@@ -1444,6 +1456,16 @@ MmsValue_getOctetStringBuffer(MmsValue* self)
     return self->value.octetString.buf;
 }
 
+uint8_t
+MmsValue_getOctetStringOctet(MmsValue* self, int octetPos)
+{
+    uint8_t octet = 0x00; /* default value, for out of range request */
+    if (octetPos < self->value.octetString.size) {
+        octet = self->value.octetString.buf[octetPos];
+    }
+    return octet;
+}
+
 MmsValue*
 MmsValue_newStructure(const MmsVariableSpecification* typeSpec)
 {