With PHP7Converter, you can convert your PHP files, which uses the old syntax mysql to the new standard mysqli.
It supports code convert, which you can only paste the code, convert it and copy it from the page. It also supports Multi-File Convert, so you can paste your Directory and simply convert all files, which are in the directory.
To install the PHP 7 Converter, you only put the files from the zip on your server, and start it via the web browser.
Put in your code and click on "Convert".
Click on the button "Convert Directory" and write in your directory, which must be convert.