diff --git a/library.properties b/library.properties
index 02b3956..8d7bfd5 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=CoAP simple library
-version=1.3.8
+version=1.3.9
 author=Hirotaka Niisato <hirotakaster@gmail.com>
 maintainer=Hirotaka Niisato <hirotakaster@gmail.com>
 sentence=Simple CoAP client/server library for generic Arduino Client hardware.