no, it should be the same the file uploader is part of mojoPortal not part of Form Wizard.
you should use web browser dev tools and look in the console for any javascript errors happening on the page
even an unrelated javascript error on the same page can prevent the file uploader javascript from working
So, the next step is find out what if any javascript errors are happening on the page and resolve those.
You did not mention how old the versions you were upgrading from are, but you should make sure you have taken care of all the important skin changes, for example if you have an older Artisteer skin it may not be compatible with the latest jquery and may need to have the jquery migrate plugin enabled as mentioned in the important skin changes. That kind of thing could be causing a script error that prevents the file uploader script form working.