diff --git a/ChangeLog.txt b/ChangeLog.txt
index 29fedaad64028621650069e10fcca1ce9ebf6fda..15b265017964f3686e8ed13d273f0a8a56b1ec6f 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -6,6 +6,11 @@
 
 JSONlab ChangeLog (key features marked by *):
 
+== JSONlab 0.5.1 (codename: Nexus Update 1), FangQ <fangq nmr mgh harvard edu> ==
+
+ 2011/10/21  fix a bug in loadjson, previous code does not use any of the acceleration
+ 2011/10/20  loadjson supports JSON collections: appendable JSON objects
+
 == JSONlab 0.5.0 (codename: Nexus), FangQ <fangq nmr mgh harvard edu> ==
 
  2011/10/16  package and release jsonlab 0.5.0
diff --git a/README.txt b/README.txt
index fc3a73daaa9359a0271f9e55d49098b1088bb7f5..494b8d6c9f813cb7ecd4902e2522fdde308e74ea 100644
--- a/README.txt
+++ b/README.txt
@@ -5,7 +5,7 @@
 
 *Copyright (c) 2011  Qianqian Fang <fangq at nmr.mgh.harvard.edu>
 *License: BSD or GNU General Public License version 3 (GPL v3), see License*.txt
-*Version: 0.5.0 (Nexus)
+*Version: 0.5.1 (Nexus)
 
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