Sync and ID3v2.3 And ID3v2.4

I had reason to change the tagging on all MP3 files from 2.4 to 2.3 recently.
I then tried using D.O. 9.5.5.0 3889 to synchronize the files to an existing folder that serves as backup for audio files.
None were selected for syncing.

I then ran a profile from Super Flexible File Synchronizer and the files were copied to the backup.

No filters were used in the sync panel. Sync subfolders and ignore seconds were selected.

I tried again with some files that I changed the case on a few tags. None were selected in D.O, all were copied with SFFS.

What parameters did you have set up in the Sync panel in Opus? Does changing the ID3 tag version actually modify the date & size of the file?

The file date was not changed. On some (but not all) the size did change.
I have one way copy, date (different) or size, ignore seconds, Sync sub-folders, no filter