diff --git a/htdocs/postDelete.php b/htdocs/postDelete.php
index aef6432b0c01195f5a61db0968e30e24728b4f8d..35096383b64851997f3a7299527d1603a37f33aa 100644
--- a/htdocs/postDelete.php
+++ b/htdocs/postDelete.php
@@ -35,6 +35,7 @@ function purgeAccountFiles()
     // c mode to open the file in write mode WITH EXCLUSIVE LOCK, but DO NOT truncate it
 
     // find and delete the line
+    $tmpLine = NULL; // Initialize tmpLine variable to avoid php notice
     $lines = file($AUTH_FILE_DONE, FILE_IGNORE_NEW_LINES);
     foreach ($lines as $key => $line) {
         if (preg_match($regex, $line) == 1) {
diff --git a/htdocs/process_email_invite.php b/htdocs/process_email_invite.php
index 28ee613caff82e1fa1cf47d5ccc6dc0a09ebe42e..fd008269f3ee226f00523292f8d61d910e7cba2a 100644
--- a/htdocs/process_email_invite.php
+++ b/htdocs/process_email_invite.php
@@ -74,7 +74,7 @@ function sendInviteMail($to, $secret, $lang)
     }
     $subject = $template->subject;
     $headers = ['From' => $from, 'To' => $to, 'Subject' => $subject,
-        'Content-Type' => 'text/html; charset=UTF-8'];
+        'Content-Type' => 'text/html; charset=UTF-8', 'Date' => date('D, d M Y H:i:s O')];
 
     // include text and HTML versions
     $text = $template->text;
diff --git a/htdocs/welcome_mails/sendmail.php b/htdocs/welcome_mails/sendmail.php
index 670b485a278f54b4286b23be0ee5dc66c08de5da..f5d7183745d7fc9f1b8af8e5f40cdd2434a7d855 100644
--- a/htdocs/welcome_mails/sendmail.php
+++ b/htdocs/welcome_mails/sendmail.php
@@ -12,7 +12,8 @@ function sendInviteMail($to, $signup_url)
         'From' => $from,
         'To' => $to,
         'Subject' => $subject,
-        "Content-Type" => "Content-Type: text/html; charset=UTF-8"
+        'Content-Type' => 'Content-Type: text/html; charset=UTF-8', 
+        'Date' => date('D, d M Y H:i:s O')
     ];
 
     // include text and HTML versions