diff --git a/Include/patchlevel.h b/Include/patchlevel.h
index db28568..8d9cd50 100644
--- a/Include/patchlevel.h
+++ b/Include/patchlevel.h
@@ -21,12 +21,12 @@
 /* Version parsed out into numeric values */
 #define PY_MAJOR_VERSION	2
 #define PY_MINOR_VERSION	5
-#define PY_MICRO_VERSION	4
-#define PY_RELEASE_LEVEL	PY_RELEASE_LEVEL_FINAL
-#define PY_RELEASE_SERIAL	0
+#define PY_MICRO_VERSION	5
+#define PY_RELEASE_LEVEL	PY_RELEASE_LEVEL_GAMMA
+#define PY_RELEASE_SERIAL	1
 
 /* Version as a string */
-#define PY_VERSION		"2.5.4"
+#define PY_VERSION		"2.5.5c1"
 
 /* Subversion Revision number of this file (not of the repository) */
 #define PY_PATCHLEVEL_REVISION  "$Revision$"
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index c88f54b..49c2d25 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -1,3 +1,8 @@
+What's New in IDLE 1.2.5c1?
+=========================
+
+*Release date: 14-Jan-2010*
+
 What's New in IDLE 1.2.4?
 =========================
 
diff --git a/Lib/idlelib/idlever.py b/Lib/idlelib/idlever.py
index 385327d..901c812 100644
--- a/Lib/idlelib/idlever.py
+++ b/Lib/idlelib/idlever.py
@@ -1 +1 @@
-IDLE_VERSION = "1.2.4"
+IDLE_VERSION = "1.2.5c1"
diff --git a/Misc/NEWS b/Misc/NEWS
index 9659f1c..c17d770 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -4,10 +4,10 @@
 
 (editors: check NEWS.help for information about editing NEWS using ReST.)
 
-What's New in Python 2.5.5?
-===========================
+What's New in Python 2.5.5c1?
+=============================
 
-*Release date: XX-XXX-20XX*
+*Release date: 14-Jan-2010*
 
 Core and builtins
 -----------------
diff --git a/README b/README
index ece68c4..a628844 100644
--- a/README
+++ b/README
@@ -1,7 +1,7 @@
-This is Python version 2.5.4
-============================
+This is Python version 2.5.5c1
+==============================
 
-Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Python Software 
+Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Python Software 
 Foundation. 
 All rights reserved.