index.php file became index.html file in httpdocs

[PatsyW]

I have built my website in Presence Builder and mobile website in Unity Mobile. In the past I was able to paste the php code into the index.php file for mobile redirection. Recently since the upgrade to 11.5, the index.php file has been missing and is replaced by index.html file. I have tried going into the backup files to retrieve the index.php file and upload it into httpdocs but it fails to redirect to mobile website after putting in the php code. And each time I re-publish the website the index.php file went missing again.
Can you help?

 

[InderS]

You will need to manually set the index.php as default document, from IIS you can set it.