#!/bin/bash

dirs=("dir1/" "dir2/" "dir3/" "dir4/" "dir5/" "dir6/" "dir7/" "dir8/")
for i in "${dirs[@]}"; do
        newFile="$(find /path/to/folder/$i -type f -ls | sort | head -n 1)"
        if test 'find "$newFile" -type f -mtime -1'
                then
                        echo -e "OK:Backup was written.n"
                else
                        echo -e "ERROR:Backups was not writtenn"
        fi
done;