Fix id3 tags to 1.1

fixtags.sh

#!/bin/bash

DIRECTORY="$1"

FixID3 () {
    iid3=$(eyeD3 -1 "$1" 2>&1 >/dev/null)
    pat="*No ID3 v1.x tag found*"

    if [[ $iid3 == $pat ]]; then eyeD3 --to-v1.1 "$1"; fi 
}
export -f FixID3

find "$DIRECTORY" -type f -iname "*.mp3" -exec bash -c 'FixID3 "$0"' {} \;

Python audio data toolkit eyeD3 is needed

pip install eyeD3