diff --git a/CHANGELOG b/CHANGELOG
index 87afc76b4..e08a3dff5 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -4,6 +4,8 @@
 
 * `Form.serialize` now works safely with forms that have "length"-named elements. [#77 state:resolved] (Peter Adrianov, John-David Dalton, kangax)
 
+*1.6.1_rc1* (March 22, 2009)
+
 * `Element#update` now takes care of SCRIPT elements in IE. [#573 state:resolved] (Martin, Tobie Langel, kangax)
 
 * Remove unused local variables from `Element.extend`. Fix one of the form tests to remove `_extendedByPrototype` by setting it to `undefined` rather than `false` (`_extendedByPrototype` being `false` does not force `Element.extend` to re-extend element). (T.J. Crowder, kangax)
diff --git a/src/constants.yml b/src/constants.yml
index 3a05ed2f8..a12207da0 100644
--- a/src/constants.yml
+++ b/src/constants.yml
@@ -1 +1 @@
-PROTOTYPE_VERSION: 1.6.0.3
+PROTOTYPE_VERSION: 1.6.1_rc2