Thank you for answering MotleyG
I will cheeck if Serato use ID3V2.4 or what.
& am not able to know If I need as long as I do not understand it.
But the general idea you are saying is that is better to keep than deleting & then realizing you need to recover data that have been deleted.
So yeah, it looks I should delete the minium & still have no clues about how to better understand how to manage the metadata to get what I want, i guess is not an easy answer & takes time (discovering that a metada field could show different data on different softwares was a revelation; this is a previous post Tag value for genre inconsistent between Mp3tag and iTunes
Thanks!