We are suddenly unable to update email templates. After pressing the Save button on the Edit email templates page, the page repaints with the old template contents. This occurs in LimeSurvey versions 4.6.3 and 3.17.1. Our webhost has recently updated the PHP version on our servers. This problem occurs with PHP versions 7.2 and 7.4. I have done some debugging and discovered that when execution gets to the update() function in emailtemplates.php line 120, $sSaveMethod is set to the empty string so that the if statement on line 121 returns false. Further investigation shows that $_POST (referenced many times in the function) is an empty array. The browser debugger shows that the form data being posted includes the contents of all the editors, a save with the value 'save', action with the value 'token' and language with the value 'en'.