Sudden new Save Dialog for Scrivener IOS

This morning, like all mornings, I wrote an article in Scrivener for IOS, compiled it, hit the export button, chose Save to Dropbox.

I got a new dialog that I have never seen before, with a big Rename option at the top. I need to rename, because I want my output file to be named, not index.txt.

The dialog would not let me change the extension.

Is this some new version of Scrivener iOS? App Store doesn’t think so. I haven’t as yet upgraded to iPadOS 15.5. Any assistance will be welcome. Thanks!

Further to this: Dropbox changed the dialog, it is not owned by Scrivener. Thanks!