I just used the file from Here to upgrade my Wamp Server to PHP 7.2.9. After I install and enable PHP 7.2.9, I look at php_error.log and I see Apache variable "${INSTALL_DIR}" is not defined.
How do I fix this problem? I am using Apache 2.4.9 and MySQL 5.6.17
Just declare 'INSTALL_DIR' inside wamp\bin\apache\apache[ your version ]\conf\httpd.conf
Define INSTALL_DIR c:/wamp [ or your wamp path ]