diff --git a/include/openthread/instance.h b/include/openthread/instance.h
index d15be0b83..d17c4a3dc 100644
--- a/include/openthread/instance.h
+++ b/include/openthread/instance.h
@@ -53,7 +53,7 @@ extern "C" {
  * @note This number versions both OpenThread platform and user APIs.
  *
  */
-#define OPENTHREAD_API_VERSION (298)
+#define OPENTHREAD_API_VERSION (299)
 
 /**
  * @addtogroup api-instance
diff --git a/include/openthread/tcp.h b/include/openthread/tcp.h
index 910831a01..3b63bc359 100644
--- a/include/openthread/tcp.h
+++ b/include/openthread/tcp.h
@@ -401,11 +401,11 @@ enum
 /**
  * Records the remote host and port for this connection.
  *
- * By default TCP Fast Open is used. This means that this function merely
- * records the remote host and port, and that the TCP connection establishment
- * handshake only happens on the first call to otTcpSendByReference(). TCP Fast
- * Open can be explicitly disabled using @p aFlags, in which case the TCP
- * connection establishment handshake is initiated immediately.
+ * Caller must wait for `otTcpEstablished` callback indicating that TCP
+ * connection establishment handshake is done before it can start sending data
+ * e.g., calling `otTcpSendByReference()`.
+ *
+ * The TCP Fast Open is not yet supported and @p aFlags is ignored.
  *
  * @param[in]  aEndpoint  A pointer to the TCP endpoint structure to connect.
  * @param[in]  aSockName  The IP address and port of the host to which to connect.