diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1f2bdfed..a0e0ea01 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 2018-08-28 version 3.1.1
+
+  * Fix msgpack_timestamp type mismatch bug (#726)
+
 # 2018-08-10 version 3.1.0
 
   * Improve documents (#687, #718)
diff --git a/README.md b/README.md
index e8fc92a3..6a8528c9 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 `msgpack` for C/C++
 ===================
 
-Version 3.1.0 [![Build Status](https://travis-ci.org/msgpack/msgpack-c.svg?branch=master)](https://travis-ci.org/msgpack/msgpack-c) [![Build status](https://ci.appveyor.com/api/projects/status/8kstcgt79qj123mw/branch/master?svg=true)](https://ci.appveyor.com/project/redboltz/msgpack-c/branch/master)
+Version 3.1.1 [![Build Status](https://travis-ci.org/msgpack/msgpack-c.svg?branch=master)](https://travis-ci.org/msgpack/msgpack-c) [![Build status](https://ci.appveyor.com/api/projects/status/8kstcgt79qj123mw/branch/master?svg=true)](https://ci.appveyor.com/project/redboltz/msgpack-c/branch/master)
 
 It's like JSON but smaller and faster.
 
diff --git a/appveyor.yml b/appveyor.yml
index 235b5bd9..a449397f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,4 +1,4 @@
-version: 3.1.0.{build}
+version: 3.1.1.{build}
 
 image:
 - Visual Studio 2015
diff --git a/include/msgpack/version_master.h b/include/msgpack/version_master.h
index fc29f07b..d145c820 100644
--- a/include/msgpack/version_master.h
+++ b/include/msgpack/version_master.h
@@ -1,3 +1,3 @@
 #define MSGPACK_VERSION_MAJOR    3
 #define MSGPACK_VERSION_MINOR    1
-#define MSGPACK_VERSION_REVISION 0
+#define MSGPACK_VERSION_REVISION 1