Just tried this on my iPad with 17.2. Had no problem loading old RM7 files originally transferred by Finder (previously iTunes) and old RM9 files transferred via Dropbox. Just used RM9.1.3 to transfer a current file via Dropbox and that also loaded OK.
Also just tried it on my iPhone with iOS 17.2 and that happily loaded the same RM9.1.3 file from Dropbox. Though rather oddly, it also has that same file listed under On Device, and it loads OK under that heading. AND, when I look, so does the iPad.