diff --git a/ChangeLog b/ChangeLog
index 214199b049..feb588e0bd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Tue Dec 27 19:32:03 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* thread.c (rb_thread_s_abort_exc, rb_thread_s_abort_exc_set):
+	  [DOC] the raised exception will be re-raised in the main thread,
+	  and then follows the ordinary exception sequence, exit status is
+	  not 0. [Bug #12991]
+
+	* thread.c (rb_thread_abort_exc_set): ditto.
+
 Tue Dec 27 19:29:54 2016  Akinori MUSHA  <knu@iDaemons.org>
 
 	* configure.in: reverse compatibility_version and current_version for
diff --git a/thread.c b/thread.c
index ba521284f7..b2d01961ff 100644
--- a/thread.c
+++ b/thread.c
@@ -2447,8 +2447,8 @@ rb_thread_s_main(VALUE klass)
  *
  *  The default is +false+.
  *
- *  When set to +true+, all threads will abort (the process will
- *  <code>exit(0)</code>) if an exception is raised in any thread.
+ *  When set to +true+, if any thread is aborted by an exception, the
+ *  raised exception will be re-raised in the main thread.
  *
  *  Can also be specified by the global $DEBUG flag or command line option
  *  +-d+.
@@ -2470,7 +2470,8 @@ rb_thread_s_abort_exc(void)
  *  call-seq:
  *     Thread.abort_on_exception= boolean   -> true or false
  *
- *  When set to +true+, all threads will abort if an exception is raised.
+ *  When set to +true+, if any thread is aborted by an exception, the
+ *  raised exception will be re-raised in the main thread.
  *  Returns the new state.
  *
  *     Thread.abort_on_exception = true
@@ -2531,10 +2532,8 @@ rb_thread_abort_exc(VALUE thread)
  *  call-seq:
  *     thr.abort_on_exception= boolean   -> true or false
  *
- *  When set to +true+, all threads (including the main program) will abort if
- *  an exception is raised in this +thr+.
- *
- *  The process will effectively <code>exit(0)</code>.
+ *  When set to +true+, if this +thr+ is aborted by an exception, the
+ *  raised exception will be re-raised in the main thread.
  *
  *  See also #abort_on_exception.
  *
diff --git a/version.h b/version.h
index a8c3541252..536a7bd8cd 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.2.7"
 #define RUBY_RELEASE_DATE "2016-12-27"
-#define RUBY_PATCHLEVEL 403
+#define RUBY_PATCHLEVEL 404
 
 #define RUBY_RELEASE_YEAR 2016
 #define RUBY_RELEASE_MONTH 12