diff --git a/ChangeLog b/ChangeLog
index e2f22db..de19a6b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2022-04-11 Tatsuhiko Kubo <cubicdaiya@gmail.com>
+
+	* bugfix: fixed invalid offset in unified format difference when difference is too large.
+
+	* 1.20 released
+
 2015-05-03 Tatsuhiko Kubo <cubicdaiya@gmail.com>
 
 	* added some minor changes.
diff --git a/dtl/variables.hpp b/dtl/variables.hpp
index cbf5a54..6720ec8 100644
--- a/dtl/variables.hpp
+++ b/dtl/variables.hpp
@@ -63,7 +63,7 @@ namespace dtl {
     /**
      * version string
      */
-    const string version = "1.19";
+    const string version = "1.20";
 
     /**
      * type of edit for SES