diff --git a/io.c b/io.c
index 71ea478ef7..4440418d96 100644
--- a/io.c
+++ b/io.c
@@ -7644,8 +7644,7 @@ rb_io_make_open_file(VALUE obj)
  *    If +mode+ parameter is given, this parameter will be bitwise-ORed.
  *
  *  :\external_encoding ::
- *    External encoding for the IO.  "-" is a synonym for the default external
- *    encoding.
+ *    External encoding for the IO.
  *
  *  :\internal_encoding ::
  *    Internal encoding for the IO.  "-" is a synonym for the default internal
diff --git a/version.h b/version.h
index 55c8aaf006..eb60ac93e5 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.4.4"
 #define RUBY_RELEASE_DATE "2018-03-20"
-#define RUBY_PATCHLEVEL 265
+#define RUBY_PATCHLEVEL 266
 
 #define RUBY_RELEASE_YEAR 2018
 #define RUBY_RELEASE_MONTH 3