diff --git a/app/Template/notification/comment_create.php b/app/Template/notification/comment_create.php
index 8b8251c63..1f890a5f4 100644
--- a/app/Template/notification/comment_create.php
+++ b/app/Template/notification/comment_create.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <?php if (! empty($comment['username'])): ?>
@@ -8,4 +10,6 @@
 
 <?= $this->text->markdown($comment['comment'], true) ?>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/comment_delete.php b/app/Template/notification/comment_delete.php
index d49f10b82..224fcdb51 100644
--- a/app/Template/notification/comment_delete.php
+++ b/app/Template/notification/comment_delete.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <h3><?= t('Comment removed') ?></h3>
@@ -5,3 +7,5 @@
 <?= $this->text->markdown($comment['comment'], true) ?>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/comment_update.php b/app/Template/notification/comment_update.php
index c22e8f1a1..87c785ccc 100644
--- a/app/Template/notification/comment_update.php
+++ b/app/Template/notification/comment_update.php
@@ -1,7 +1,11 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <h3><?= t('Comment updated') ?></h3>
 
 <?= $this->text->markdown($comment['comment'], true) ?>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/comment_user_mention.php b/app/Template/notification/comment_user_mention.php
index a3f387beb..afa3aa7e3 100644
--- a/app/Template/notification/comment_user_mention.php
+++ b/app/Template/notification/comment_user_mention.php
@@ -1,7 +1,11 @@
+<html>
+<body>
 <h2><?= t('You were mentioned in a comment on the task #%d', $task['id']) ?></h2>
 
 <p><?= $this->text->e($task['title']) ?></p>
 
 <?= $this->text->markdown($comment['comment'], true) ?>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/subtask_create.php b/app/Template/notification/subtask_create.php
index 094ac5436..f5b91d340 100644
--- a/app/Template/notification/subtask_create.php
+++ b/app/Template/notification/subtask_create.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <h3><?= t('New sub-task') ?></h3>
@@ -14,4 +16,6 @@
     <?php endif ?>
 </ul>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/subtask_delete.php b/app/Template/notification/subtask_delete.php
index 1f5b12c44..eaf51e447 100644
--- a/app/Template/notification/subtask_delete.php
+++ b/app/Template/notification/subtask_delete.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <h3><?= t('Subtask removed') ?></h3>
@@ -9,3 +11,5 @@
 </ul>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/subtask_update.php b/app/Template/notification/subtask_update.php
index a69567928..95663e80f 100644
--- a/app/Template/notification/subtask_update.php
+++ b/app/Template/notification/subtask_update.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <h3><?= t('Sub-task updated') ?></h3>
@@ -20,4 +22,6 @@
     <?php endif ?>
 </ul>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_assignee_change.php b/app/Template/notification/task_assignee_change.php
index 608d8d722..de47e56a6 100644
--- a/app/Template/notification/task_assignee_change.php
+++ b/app/Template/notification/task_assignee_change.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <ul>
@@ -17,4 +19,6 @@
     <?= $this->text->markdown($task['description'], true) ?: t('There is no description.') ?>
 <?php endif ?>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_close.php b/app/Template/notification/task_close.php
index b5763c75c..efa27aa3b 100644
--- a/app/Template/notification/task_close.php
+++ b/app/Template/notification/task_close.php
@@ -1,5 +1,9 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p><?= t('The task #%d have been closed.', $task['id']) ?></p>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_create.php b/app/Template/notification/task_create.php
index e56c252d6..3a34dbe63 100644
--- a/app/Template/notification/task_create.php
+++ b/app/Template/notification/task_create.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <ul>
@@ -40,4 +42,6 @@
     <?= $this->text->markdown($task['description'], true) ?>
 <?php endif ?>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_file_create.php b/app/Template/notification/task_file_create.php
index c552546ce..c8f6b30d4 100644
--- a/app/Template/notification/task_file_create.php
+++ b/app/Template/notification/task_file_create.php
@@ -1,5 +1,9 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p><?= t('New attachment added "%s"', $file['name']) ?></p>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_file_destroy.php b/app/Template/notification/task_file_destroy.php
index dbd79c5e4..17d046303 100644
--- a/app/Template/notification/task_file_destroy.php
+++ b/app/Template/notification/task_file_destroy.php
@@ -1,5 +1,9 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p><?= t('Attachment removed "%s"', $file['name']) ?></p>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_internal_link_create_update.php b/app/Template/notification/task_internal_link_create_update.php
index 4a88ab789..5273dc349 100644
--- a/app/Template/notification/task_internal_link_create_update.php
+++ b/app/Template/notification/task_internal_link_create_update.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p>
@@ -7,3 +9,5 @@
 </p>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_internal_link_delete.php b/app/Template/notification/task_internal_link_delete.php
index 2b4b84442..b3413c78b 100644
--- a/app/Template/notification/task_internal_link_delete.php
+++ b/app/Template/notification/task_internal_link_delete.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p>
@@ -7,3 +9,5 @@
 </p>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_move_column.php b/app/Template/notification/task_move_column.php
index 7159cb06a..e4281d57c 100644
--- a/app/Template/notification/task_move_column.php
+++ b/app/Template/notification/task_move_column.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <ul>
@@ -8,4 +10,6 @@
     <li><?= t('Task position:').' '.$this->text->e($task['position']) ?></li>
 </ul>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_move_position.php b/app/Template/notification/task_move_position.php
index 7159cb06a..e4281d57c 100644
--- a/app/Template/notification/task_move_position.php
+++ b/app/Template/notification/task_move_position.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <ul>
@@ -8,4 +10,6 @@
     <li><?= t('Task position:').' '.$this->text->e($task['position']) ?></li>
 </ul>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_move_project.php b/app/Template/notification/task_move_project.php
index 64037bd62..96f4e5440 100644
--- a/app/Template/notification/task_move_project.php
+++ b/app/Template/notification/task_move_project.php
@@ -1,5 +1,9 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p><?= t('Task #%d "%s" has been moved to the project "%s"', $task['id'], $task['title'], $task['project_name']) ?></p>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_move_swimlane.php b/app/Template/notification/task_move_swimlane.php
index cdf165590..1715b9b53 100644
--- a/app/Template/notification/task_move_swimlane.php
+++ b/app/Template/notification/task_move_swimlane.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <ul>
@@ -16,4 +18,6 @@
     <li><?= t('Task position:').' '.$this->text->e($task['position']) ?></li>
 </ul>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_open.php b/app/Template/notification/task_open.php
index 5bd0d1a4f..af0efadda 100644
--- a/app/Template/notification/task_open.php
+++ b/app/Template/notification/task_open.php
@@ -1,5 +1,9 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <p><?= t('The task #%d have been opened.', $task['id']) ?></p>
 
 <?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_overdue.php b/app/Template/notification/task_overdue.php
index cb954c0b5..88140af03 100644
--- a/app/Template/notification/task_overdue.php
+++ b/app/Template/notification/task_overdue.php
@@ -1,3 +1,5 @@
+<html>
+<body>
 <h2><?= t('Overdue tasks for the project(s) "%s"', $project_name) ?></h2>
 
 <table style="font-size: .8em; table-layout: fixed; width: 100%; border-collapse: collapse; border-spacing: 0; margin-bottom: 20px;" cellpadding=5 cellspacing=1>
@@ -34,4 +36,6 @@
             </td>
         </tr>
     <?php endforeach ?>
-</table>
\ No newline at end of file
+</table>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_update.php b/app/Template/notification/task_update.php
index 8d39b1521..86b7466e2 100644
--- a/app/Template/notification/task_update.php
+++ b/app/Template/notification/task_update.php
@@ -1,4 +1,8 @@
+<html>
+<body>
 <h2><?= $this->text->e($task['title']) ?> (#<?= $task['id'] ?>)</h2>
 
 <?= $this->render('task/changes', array('changes' => $changes, 'task' => $task, 'public' => true)) ?>
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
diff --git a/app/Template/notification/task_user_mention.php b/app/Template/notification/task_user_mention.php
index dfd6e723f..dc72169a2 100644
--- a/app/Template/notification/task_user_mention.php
+++ b/app/Template/notification/task_user_mention.php
@@ -1,7 +1,11 @@
+<html>
+<body>
 <h2><?= t('You were mentioned in the task #%d', $task['id']) ?></h2>
 <p><?= $this->text->e($task['title']) ?></p>
 
 <h2><?= t('Description') ?></h2>
 <?= $this->text->markdown($task['description'], true) ?>
 
-<?= $this->render('notification/footer', array('task' => $task)) ?>
\ No newline at end of file
+<?= $this->render('notification/footer', array('task' => $task)) ?>
+</body>
+</html>
\ No newline at end of file
