diff --git a/history.en.md b/history.en.md
index 61c052045..710ec4ac0 100644
--- a/history.en.md
+++ b/history.en.md
@@ -1,6 +1,8 @@
 # History
 
  - master/HEAD
+ - 3.5.31 (2020.10.4)
+   * Restore group tab title correctly. (regression on 3.5.30)
  - 3.5.30 (2020.10.4)
    * Add ability to specify arbitrary title for the sidebar page with the parameter `title`, like `ext+treestyletab:tabbar?title=...`. This is for better compatibiliy with helper addons using TST's sidebar page e.g. [Tree Style Tab in Separate Window](https://addons.mozilla.org/firefox/addon/tst-in-separate-window/).
    * Load sidebar page with the chosen builtin theme immediately when it is loaded via `ext+treestyletab:tabbar` URL. This is for better compatibiliy with helper addons using TST's sidebar page e.g. [Tree Style Tab in Separate Window](https://addons.mozilla.org/firefox/addon/tst-in-separate-window/).
diff --git a/history.ja.md b/history.ja.md
index 384454788..614a6e3c3 100644
--- a/history.ja.md
+++ b/history.ja.md
@@ -1,6 +1,8 @@
 # 更新履歴
 
  - master/HEAD
+ - 3.5.31 (2020.10.4)
+   * グループ化用タブのタイトルが正しく復元されなくなっていたのを修正（3.5.30での後退バグ）
  - 3.5.30 (2020.10.4)
    * サイドバー用のページを読み込む際、`ext+treestyletab:tabbar?title=...` のようにURLパラメータ `title` でページのタイトルを制御できるようにした（[Tree Style Tab in Separate Window](https://addons.mozilla.org/firefox/addon/tst-in-separate-window/)などのアドオンとの互換性向上のため）
    * `ext+treestyletab:tabbar` と指定してサイドバー用のページを読み込む際、選択された組み込みのテーマを反映した状態でページを読み込むようにした（[Tree Style Tab in Separate Window](https://addons.mozilla.org/firefox/addon/tst-in-separate-window/)などのアドオンとの互換性向上のため）
diff --git a/webextensions/manifest.json b/webextensions/manifest.json
index b3c79507d..7c1854f9a 100644
--- a/webextensions/manifest.json
+++ b/webextensions/manifest.json
@@ -1,7 +1,7 @@
 {
   "manifest_version": 2,
   "name": "__MSG_extensionName__",
-  "version": "3.5.30",
+  "version": "3.5.31",
   "author": "YUKI \"Piro\" Hiroshi",
   "description": "__MSG_extensionDescription__",
   "permissions": [