autodiscover.php

<?php
$postData = file_get_contents("php://input"); //Autodiscover requests are HTTP posts with XML content
$xml = simplexml_load_string($postData);
$user = $xml->Request->EMailAddress; //copy the email address from the request into a variable
$domain = substr($user, strpos($user, '@') + 1); // get the domain name from the email address

//set Content-Type
header("Content-Type: application/xml"); ?>
<?php echo '<?xml version="1.0" encoding="utf-8" ?>'; ?>

<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
  <Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a">
   <Account>
      <AccountType>email</AccountType>
      <Action>settings</Action>
      <Protocol>
         <Type>IMAP</Type>
         <Server>mail.example.tld</Server>
         <Port>993</Port>
         <DomainRequired>on</DomainRequired>
         <Domain><?php echo $domain; ?></Domain>
         <LoginName><?php echo $user; ?></LoginName>
         <SPA>off</SPA>
         <SSL>on</SSL>
         <Encryption>TLS</Encryption>
         <AuthRequired>on</AuthRequired>
      </Protocol>
      <Protocol>
         <Type>SMTP</Type>
         <Server>mail.example.tld</Server>
         <Port>587</Port>
         <DomainRequired>on</DomainRequired>
         <Domain><?php echo $domain; ?></Domain>
         <LoginName><?php echo $user; ?></LoginName>
         <SPA>off</SPA>
         <Encryption>TLS</Encryption>
         <AuthRequired>on</AuthRequired>
         <SMTPLast>on</SMTPLast>
      </Protocol>
   </Account>
</Response>
</Autodiscover>