diff --git a/README.md b/README.md
index 575aacf..e348521 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ Installation
 
 ### Apache Webserver
 
-You need an Apache webserver with PHP5 preconfigures. You can then configure your Virtual Host like this
+You need an Apache webserver with (at least) PHP 7.3 preconfigured. You can then configure your Virtual Host like this
 
 ```
 <VirtualHost *:443>
diff --git a/autodiscover.xml.php b/autodiscover.xml.php
index aedf5e3..4bf2487 100644
--- a/autodiscover.xml.php
+++ b/autodiscover.xml.php
@@ -16,7 +16,8 @@
 $xml = str_replace("%TTL%", $config['ttl'], $xml);
 
 
-$xml = str_replace("%SERVER/SMTP/SSL_ON%", isOnOrOff($config['server']['smtp']['socket'] == "SSL"), $xml);
+$xml = str_replace("%SERVER/SMTP/ENCRYPTION%", str_replace("STARTTLS", "TLS", $config['server']['smtp']['socket']), $xml);
+
 $xml = str_replace("%SERVER/IMAP/SSL_ON%", isOnOrOff($config['server']['imap']['socket'] == "SSL"), $xml);
 
 $xml = str_replace("%SERVER/IMAP/DOMAIN_REQUIRED%", isOnOrOff($config['server']['domain_required']), $xml);
@@ -55,16 +56,24 @@ function isOnOrOff ($value) {
 }
 
 function loadConfig () {
-  return json_decode(implode('', file('settings.json')), true);
+  $content = file_get_contents('settings.json');
+  if ($content === FALSE) {
+    throw new Exception('Error reading settings.json.');
+  }
+  return json_decode($content, true, 512, JSON_THROW_ON_ERROR);
 }
 
 function loadTemplate ($file) {
-  return implode("",file($file));
+  $content = file_get_contents($file);
+  if ($content === FALSE) {
+    throw new Exception('Error reading template file.');
+  }
+  return $content;
 }
 
 function determineTemplateFile () {
 
-  $template = array_key_exists('template', $_GET) ? $_GET['template'] : null;
+  $template = $_GET['template'] ?? null;
   
   switch($template) {
 
@@ -84,7 +93,7 @@ function determineTemplateFile () {
 
 function getRequestEmail () {
 
-  $email = array_key_exists('email', $_GET) ? $_GET['email'] : null;
+  $email = $_GET['email'] ?? null;
   return filter_var($email, FILTER_VALIDATE_EMAIL);
 
 }
diff --git a/mail/autodiscover.xml b/mail/autodiscover.xml
index 2d8aa65..15a96b2 100644
--- a/mail/autodiscover.xml
+++ b/mail/autodiscover.xml
@@ -150,7 +150,7 @@ If this value is true, then the SMTP server requires that email be downloaded be
   <Port>%SERVER/SMTP/PORT%</Port>
   <DomainRequired>%SERVER/SMTP/DOMAIN_REQUIRED%</DomainRequired>
   <SPA>off</SPA>
-  <SSL>%SERVER/SMTP/SSL_ON%</SSL>
+  <Encryption>%SERVER/SMTP/ENCRYPTION%</Encryption>
   <AuthRequired>on</AuthRequired>
   <UsePOPAuth>on</UsePOPAuth>
   <SMTPLast>off</SMTPLast>