Update ChangeLog for 4.0.4.
diff --git a/ChangeLog b/ChangeLog
index cd8f695..8ed42cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,7 +4,12 @@
 
     https://github.com/jemalloc/jemalloc
 
-* 4.0.4 (XXX)
+* 4.0.4 (October 24, 2015)
+
+  This bugfix release fixes another xallocx() regression.  No other regressions
+  have come to light in over a month, so this is likely a good starting point
+  for people who prefer to wait for "dot one" releases with all the major issues
+  shaken out.
 
   Bug fixes:
   - Fix xallocx(..., MALLOCX_ZERO to zero the last full trailing page of large