diff --git a/docs/guide-fr/tutorial-i18n.md b/docs/guide-fr/tutorial-i18n.md
index 2566c7b..25a538d 100644
--- a/docs/guide-fr/tutorial-i18n.md
+++ b/docs/guide-fr/tutorial-i18n.md
@@ -240,7 +240,7 @@ Vous pouvez aussi spécifier un motif personnalisé pour formater l'heure :
 echo \Yii::t('app', 'It is {0,date,HH:mm}', time());
 ```
 
-Voir [Formatting reference](http://icu-project.org/apiref/icu4c/classicu_1_1SimpleDateFormat.html#details).
+Voir [Formatting reference](https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/classicu_1_1SimpleDateFormat.html#details).
 
 
 #### Prononciation <span id="spellout"></span>
diff --git a/docs/guide-ja/tutorial-i18n.md b/docs/guide-ja/tutorial-i18n.md
index 04c9ffa..0265f77 100644
--- a/docs/guide-ja/tutorial-i18n.md
+++ b/docs/guide-ja/tutorial-i18n.md
@@ -357,7 +357,7 @@ echo \Yii::t('app', 'It is {0,date,HH:mm}', time());
 // 日本語出力: '現在 22:37 です。'
 ```
 
-[書式のリファレンス](http://icu-project.org/apiref/icu4c/classicu_1_1SimpleDateFormat.html#details).
+[書式のリファレンス](https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/classicu_1_1SimpleDateFormat.html#details).
 
 
 #### 綴り <span id="spellout"></span>
diff --git a/docs/guide-ru/tutorial-i18n.md b/docs/guide-ru/tutorial-i18n.md
index 3240671..cd98539 100644
--- a/docs/guide-ru/tutorial-i18n.md
+++ b/docs/guide-ru/tutorial-i18n.md
@@ -202,7 +202,7 @@ echo \Yii::t('app', 'It is {0, time, short}', time());
 echo \Yii::t('app', 'It is {0, date,HH:mm}', time());
 ```
 
-[Описание форматирования](http://icu-project.org/apiref/icu4c/classicu_1_1SimpleDateFormat.html#details).
+[Описание форматирования](https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/classicu_1_1SimpleDateFormat.html#details).
 
 
 #### Числа прописью
diff --git a/docs/guide-zh-CN/tutorial-i18n.md b/docs/guide-zh-CN/tutorial-i18n.md
index 1fc8c2d..f73e524 100644
--- a/docs/guide-zh-CN/tutorial-i18n.md
+++ b/docs/guide-zh-CN/tutorial-i18n.md
@@ -325,7 +325,7 @@ echo \Yii::t('app', 'It is {0, time, short}', time());
 echo \Yii::t('app', 'It is {0, date, HH:mm}', time());
 ```
 
-[格式化参考](http://icu-project.org/apiref/icu4c/classicu_1_1SimpleDateFormat.html#details)。
+[格式化参考](https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/classicu_1_1SimpleDateFormat.html#details)。
 
 
 #### 拼写（Spellout） <span id="spellout"></span>
diff --git a/docs/guide/tutorial-i18n.md b/docs/guide/tutorial-i18n.md
index c7c523e..29fcd14 100644
--- a/docs/guide/tutorial-i18n.md
+++ b/docs/guide/tutorial-i18n.md
@@ -325,7 +325,7 @@ You can also specify a custom pattern to format the time value:
 echo \Yii::t('app', 'It is {0,date,HH:mm}', time());
 ```
 
-[Formatting reference](http://icu-project.org/apiref/icu4c/classicu_1_1SimpleDateFormat.html#details).
+[Formatting reference](https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/classicu_1_1SimpleDateFormat.html#details).
 
 
 #### Spellout <span id="spellout"></span>