diff --git a/ChangeLog b/ChangeLog
index e2a7b161cc..145b169c7b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+Sat Dec 21 03:46:14 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/date/date_strptime.c (date__strptime_internal): unset
+	  case-insensitive flag for [:alpha:], which already implies both
+	  cases, to get rid of backtrack explosion.  [ruby-core:58984]
+	  [Bug #9221]
+
+Sat Dec 21 03:46:14 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/date/date_parse.c (parse_time): unset case-insensitive flag
+	  for [:alpha:], which already implies both cases, to get rid of
+	  backtrack explosion.  [ruby-core:58876] [Bug #9221]
+
 Fri Dec 13 00:23:01 2013  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* enumerator.c (enumerator_with_index): try to convert given offset to
diff --git a/ext/date/date_parse.c b/ext/date/date_parse.c
index 29dbb239bb..3003b45239 100644
--- a/ext/date/date_parse.c
+++ b/ext/date/date_parse.c
@@ -765,9 +765,9 @@ parse_time(VALUE str, VALUE hash)
 		   "("
 		     "(?:gmt|utc?)?[-+]\\d+(?:[,.:]\\d+(?::\\d+)?)?"
 		   "|"
-		     "[[:alpha:].\\s]+(?:standard|daylight)\\stime\\b"
+		     "(?-i:[[:alpha:].\\s]+)(?:standard|daylight)\\stime\\b"
 		   "|"
-		     "[[:alpha:]]+(?:\\sdst)?\\b"
+		     "(?-i:[[:alpha:]]+)(?:\\sdst)?\\b"
 		   ")"
 		")?";
     static VALUE pat = Qnil;
diff --git a/ext/date/date_strptime.c b/ext/date/date_strptime.c
index c6a5969172..3e1b0f85ea 100644
--- a/ext/date/date_strptime.c
+++ b/ext/date/date_strptime.c
@@ -567,8 +567,8 @@ date__strptime_internal(const char *str, size_t slen,
 		    static const char pat_source[] =
 			"\\A("
 			"(?:gmt|utc?)?[-+]\\d+(?:[,.:]\\d+(?::\\d+)?)?"
-			"|[[:alpha:].\\s]+(?:standard|daylight)\\s+time\\b"
-			"|[[:alpha:]]+(?:\\s+dst)?\\b"
+			"|(?-i:[[:alpha:].\\s]+)(?:standard|daylight)\\s+time\\b"
+			"|(?-i:[[:alpha:]]+)(?:\\s+dst)?\\b"
 			")";
 		    static VALUE pat = Qnil;
 		    VALUE m, b;
diff --git a/version.h b/version.h
index 25fd4ca495..f46601a4ad 100644
--- a/version.h
+++ b/version.h
@@ -1,10 +1,10 @@
 #define RUBY_VERSION "2.0.0"
-#define RUBY_RELEASE_DATE "2013-12-14"
-#define RUBY_PATCHLEVEL 359
+#define RUBY_RELEASE_DATE "2013-12-21"
+#define RUBY_PATCHLEVEL 360
 
 #define RUBY_RELEASE_YEAR 2013
 #define RUBY_RELEASE_MONTH 12
-#define RUBY_RELEASE_DAY 14
+#define RUBY_RELEASE_DAY 21
 
 #include "ruby/version.h"