diff --git a/Doc/release_note_en.md b/Doc/release_note_en.md
index 9fe3e75a..9d1261b1 100644
--- a/Doc/release_note_en.md
+++ b/Doc/release_note_en.md
@@ -4,6 +4,7 @@ English / [Japanese](release_note_ja.md)
 * #332 stop buffering on io.open("w") (Thx! @spiegel-im-spiegel)
 * #333 Fix file:seek() did not work on reading as expected (Thx! @erw7)
 * #333 Fix file:close()'s return value was invalid. (Thx! @erw7)
+* #319 Impl utf8.len()
 
 NYAGOS 4.3.3\_0
 ===============
diff --git a/Doc/release_note_ja.md b/Doc/release_note_ja.md
index 83baf7b6..ec66ec5c 100644
--- a/Doc/release_note_ja.md
+++ b/Doc/release_note_ja.md
@@ -4,6 +4,7 @@
 * #332 io.open("w") でバッファリングしないようにした (Thx! @spiegel-im-spiegel)
 * #333 Fix file:seek() が読み取り時に期待どおり同しなかった点を修正 (Thx! @erw7)
 * #333 Fix file:close() の戻り値がおかしかった点を修正 (Thx! @erw7)
+* #319 utf8.len() を実装
 
 NYAGOS 4.3.3\_0
 ===============