MP3 Tag questions: Does an app us ID3v1 or ID3v2??

[Snacko]

I had loaded all my music manually to my DI SD Card, and realized that I needed to fix all the Tags to make this more useful. The DI Music Player had all kinds of Genres and Artist Names that were just spelled differently, which just made it too large and confusing...

So, I used Mp3tag to update all of the Artists, Titles, and Genres. And Copied my music all back onto my DI.

But the Music Player still shows all of the old Artists, and Genres!! So, I have a few questions:

1. Since there are 2 sets of MP3 Tags, how do you know which Tag (ID3v1 or ID3v2) a program (like Media Monkey, etc..) or an App (like DI Music Player, etc..) will use to read and display???
2. Do you need to Delete one set of Tags, or the other? To force programs to use the one with the Tag data??
3. Do I need to somehow delete the cached Tag info in Music Player?

Thanks,
Snacko