Doesn't work in WP 4.3.1

Hi!

You’re in the list view of the Media Library, right?

There’s a ‘Filename’ field now available to you. Enter a new name there, check the checkbox next to the item(s) you wish to rename, then choose ‘Rename’ from the Bulk Actions select box.

The files rename via AJAX, so after a few moments you’ll see green, confirmation icons appear next to the filenames.

I’m on version 4.3.1 as well and it works for me.