Replace old file with new file

Question

I am trying to write a script to replace old files content with new files content which is appearing in the following format:

Old file : something.txt
New file : s

Answer 1

Invalid question Invalid answer

source 1

@echo off
set FOLDER_PATH=D:\test
cd /d "%FOLDER_PATH%"
ren "*.txt.new" "*.txt"

source 2

@echo off
set FOLDER_PATH=D:\test
cd /d "%FOLDER_PATH%"
ren "*.txt" "*.txt.new"