diff --git a/data/web/autodiscover.php b/data/web/autodiscover.php
index fd4181f6..92328e7f 100644
--- a/data/web/autodiscover.php
+++ b/data/web/autodiscover.php
@@ -1,102 +1,112 @@
 <?php
 require_once 'inc/vars.inc.php';
 require_once 'inc/functions.inc.php';
-if (file_exists('inc/vars.local.inc.php')) {
-	include_once 'inc/vars.local.inc.php';
+if(file_exists('inc/vars.local.inc.php')) {
+  include_once 'inc/vars.local.inc.php';
 }
 
 error_reporting(0);
 
 $data = trim(file_get_contents("php://input"));
 
-if ($autodiscover_config['useEASforOutlook'] == 'yes' &&
-  preg_match('/(Outlook|Office).+(1[5-9]\.)/', $_SERVER['HTTP_USER_AGENT']) &&
-  strpos($_SERVER['HTTP_USER_AGENT'], 'Mac') === false) {
-	$autodiscover_config['autodiscoverType'] = 'activesync';
-}
-else {
-	$autodiscover_config['autodiscoverType'] = 'imap';
+// Desktop client needs IMAP, unless it's Outlook 2013 or higher on Windows
+if (strpos($data, 'autodiscover/outlook/responseschema')) { // desktop client
+  $autodiscover_config['autodiscoverType'] = 'imap';
+  if ($autodiscover_config['useEASforOutlook'] == 'yes' &&
+  // Office for macOS does not support EAS
+  strpos($_SERVER['HTTP_USER_AGENT'], 'Mac') === false &&
+  // Outlook 2013 (version 15) or higher
+  preg_match('/(Outlook|Office).+1[5-9]\./', $_SERVER['HTTP_USER_AGENT'])) {
+    $autodiscover_config['autodiscoverType'] = 'activesync';
+  }
 }
 
-$dsn = "$database_type:host=$database_host;dbname=$database_name";
+$dsn = $database_type . ":host=" . $database_host . ";dbname=" . $database_name;
 $opt = [
-		PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
-		PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
-		PDO::ATTR_EMULATE_PREPARES   => false,
+  PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
+  PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+  PDO::ATTR_EMULATE_PREPARES   => false,
 ];
 $pdo = new PDO($dsn, $database_user, $database_pass, $opt);
 $login_user = strtolower(trim($_SERVER['PHP_AUTH_USER']));
-$as = check_login($login_user, $_SERVER['PHP_AUTH_PW']);
+$login_role = check_login($login_user, $_SERVER['PHP_AUTH_PW']);
 
-if (!isset($_SERVER['PHP_AUTH_USER']) OR $as !== "user") {
-	header('WWW-Authenticate: Basic realm=""');
-	header('HTTP/1.0 401 Unauthorized');
-	exit;
+if (!isset($_SERVER['PHP_AUTH_USER']) OR $login_role !== "user") {
+  header('WWW-Authenticate: Basic realm=""');
+  header('HTTP/1.0 401 Unauthorized');
+  exit(0);
 }
 else {
-	if (isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
-		if ($as === "user") {
+  if (isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
+    if ($login_role === "user") {
       header("Content-Type: application/xml");
-      echo '<?xml version="1.0" encoding="utf-8" ?><Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">';
-
-      if (!$data) {
+      echo '<?xml version="1.0" encoding="utf-8" ?>' . PHP_EOL;
+?>
+<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
+<?php
+      if(!$data) {
         list($usec, $sec) = explode(' ', microtime());
-        echo '<Response>';
-        echo '<Error Time="' . date('H:i:s', $sec) . substr($usec, 0, strlen($usec) - 2) . '" Id="2477272013">';
-        echo '<ErrorCode>600</ErrorCode><Message>Invalid Request</Message><DebugData /></Error>';
-        echo '</Response>';
-        echo '</Autodiscover>';
+?>
+  <Response>
+    <Error Time="<?=date('H:i:s', $sec) . substr($usec, 0, strlen($usec) - 2);?>" Id="2477272013">
+      <ErrorCode>600</ErrorCode>
+      <Message>Invalid Request</Message>
+      <DebugData />
+    </Error>
+  </Response>
+</Autodiscover>
+<?php
         exit(0);
       }
       $discover = new SimpleXMLElement($data);
       $email = $discover->Request->EMailAddress;
 
       if ($autodiscover_config['autodiscoverType'] == 'imap') {
-      ?>
+?>
   <Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a">
-      <User>
-          <DisplayName><?php echo $displayname; ?></DisplayName>
-      </User>
-      <Account>
-          <AccountType>email</AccountType>
-          <Action>settings</Action>
-          <Protocol>
-              <Type>IMAP</Type>
-              <Server><?php echo $autodiscover_config['imap']['server']; ?></Server>
-              <Port><?php echo $autodiscover_config['imap']['port']; ?></Port>
-              <DomainRequired>off</DomainRequired>
-              <LoginName><?php echo $email; ?></LoginName>
-              <SPA>off</SPA>
-              <SSL><?php echo $autodiscover_config['imap']['ssl']; ?></SSL>
-              <AuthRequired>on</AuthRequired>
-          </Protocol>
-          <Protocol>
-              <Type>SMTP</Type>
-              <Server><?php echo $autodiscover_config['smtp']['server']; ?></Server>
-              <Port><?php echo $autodiscover_config['smtp']['port']; ?></Port>
-              <DomainRequired>off</DomainRequired>
-              <LoginName><?php echo $email; ?></LoginName>
-              <SPA>off</SPA>
-              <SSL><?php echo $autodiscover_config['smtp']['ssl']; ?></SSL>
-              <AuthRequired>on</AuthRequired>
-              <UsePOPAuth>on</UsePOPAuth>
-              <SMTPLast>off</SMTPLast>
-          </Protocol>
-          <Protocol>
-              <Type>CalDAV</Type>
-              <Server>https://<?php echo $mailcow_hostname; ?>/SOGo/dav/<?php echo $email; ?>/Calendar</Server>
-              <DomainRequired>off</DomainRequired>
-              <LoginName><?php echo $email; ?></LoginName>
-          </Protocol>
-          <Protocol>
-              <Type>CardDAV</Type>
-              <Server>https://<?php echo $mailcow_hostname; ?>/SOGo/dav/<?php echo $email; ?>/Contacts</Server>
-              <DomainRequired>off</DomainRequired>
-              <LoginName><?php echo $email; ?></LoginName>
-          </Protocol>
-      </Account>
+    <User>
+      <DisplayName><?=$displayname;?></DisplayName>
+    </User>
+    <Account>
+      <AccountType>email</AccountType>
+      <Action>settings</Action>
+      <Protocol>
+        <Type>IMAP</Type>
+        <Server><?=$autodiscover_config['imap']['server'];?></Server>
+        <Port><?=$autodiscover_config['imap']['port'];?></Port>
+        <DomainRequired>off</DomainRequired>
+        <LoginName><?=$email;?></LoginName>
+        <SPA>off</SPA>
+        <SSL><?=$autodiscover_config['imap']['ssl'];?></SSL>
+        <AuthRequired>on</AuthRequired>
+      </Protocol>
+      <Protocol>
+        <Type>SMTP</Type>
+        <Server><?=$autodiscover_config['smtp']['server'];?></Server>
+        <Port><?=$autodiscover_config['smtp']['port'];?></Port>
+        <DomainRequired>off</DomainRequired>
+        <LoginName><?=$email;?></LoginName>
+        <SPA>off</SPA>
+        <SSL><?=$autodiscover_config['smtp']['ssl'];?></SSL>
+        <AuthRequired>on</AuthRequired>
+        <UsePOPAuth>on</UsePOPAuth>
+        <SMTPLast>off</SMTPLast>
+      </Protocol>
+      <Protocol>
+        <Type>CalDAV</Type>
+        <Server>https://<?=$mailcow_hostname;?>/SOGo/dav/<?=$email;?>/Calendar</Server>
+        <DomainRequired>off</DomainRequired>
+        <LoginName><?=$email;?></LoginName>
+      </Protocol>
+      <Protocol>
+        <Type>CardDAV</Type>
+        <Server>https://<?=$mailcow_hostname;?>/SOGo/dav/<?=$email;?>/Contacts</Server>
+        <DomainRequired>off</DomainRequired>
+        <LoginName><?=$email;?></LoginName>
+      </Protocol>
+    </Account>
   </Response>
-      <?php
+<?php
       }
       else if ($autodiscover_config['autodiscoverType'] == 'activesync') {
         $username = trim($email);
@@ -114,29 +124,29 @@ else {
         else {
           $displayname = $email;
         }
-      ?>
+?>
   <Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/mobilesync/responseschema/2006">
-      <Culture>en:en</Culture>
-      <User>
-          <DisplayName><?php echo $displayname; ?></DisplayName>
-          <EMailAddress><?php echo $email; ?></EMailAddress>
-      </User>
-      <Action>
-          <Settings>
-              <Server>
-                  <Type>MobileSync</Type>
-                  <Url><?php echo $autodiscover_config['activesync']['url']; ?></Url>
-                  <Name><?php echo $autodiscover_config['activesync']['url']; ?></Name>
-              </Server>
-          </Settings>
-      </Action>
+    <Culture>en:en</Culture>
+    <User>
+      <DisplayName><?=$displayname;?></DisplayName>
+      <EMailAddress><?=$email;?></EMailAddress>
+    </User>
+    <Action>
+      <Settings>
+        <Server>
+        <Type>MobileSync</Type>
+        <Url><?=$autodiscover_config['activesync']['url'];?></Url>
+        <Name><?=$autodiscover_config['activesync']['url'];?></Name>
+        </Server>
+      </Settings>
+    </Action>
   </Response>
-      <?php
+<?php
       }
-      ?>
+?>
 </Autodiscover>
 <?php
-		}
-	}
+    }
+  }
 }
 ?>