batch script to rename the data inside a text file

I have written a windows batch code to rename the folders and files recursively from V34 to 35 and so on..and but I need to change same V34 to 35 inside a text file,which is residing inside the files

Folder---file--text file(Inside the text file need to change the V34 content to V35)

Please find the below code which I have written and let me know for the changes

@echo off
setlocal disableDelayedExpansion
set "old=V34"
set "new=V35"
for /f "delims=" %%F in ('dir /b /s *. *.xslt ^| sort /r') do (
  set "source=%%F"
  set "oldname=%%~nxF"
  setlocal enableDelayedExpansion
  set "newname=!oldname:%old%=%new%!"
  if /i "!newname!" neq "!oldname!" (
    echo ren "!source!" "!newname!"
    ren "!source!" "!newname!"
  ) )

for /f "delims=" %%i in (.*) do (
    set "source=%%i"
    setlocal enabledelayedexpansion
    set "newname=!oldname:%old%=%new%!"
    echo ren "!source!" "!newname!"
    ren "!source!" "!newname!"
    endlocal
)

  endlocal