diff --git a/history.en.md b/history.en.md
index bfc013f5..b33093b0 100644
--- a/history.en.md
+++ b/history.en.md
@@ -1,6 +1,7 @@
 # History
 
  - master/HEAD
+   * Drop support for Firefox 44 and older versions.
  - 0.17.2016083101
    * Fix broken tab color of Firefox 51 and later (due to [bug 1297157](https://bugzilla.mozilla.org/show_bug.cgi?id=1297157).)
  - 0.17.2016083001
diff --git a/history.ja.md b/history.ja.md
index e1bf1bcd..413edffe 100644
--- a/history.ja.md
+++ b/history.ja.md
@@ -1,6 +1,7 @@
 # 更新履歴
 
  - master/HEAD
+   * Firefox 44より古いバージョンのサポートを終了
  - 0.17.2016083101
    * Firefox 51以降でタブの色がおかしくなる問題を修正（[bug 1297157](https://bugzilla.mozilla.org/show_bug.cgi?id=1297157)への追従）
  - 0.17.2016083001