Update PAK file via chunk downloader

I successfully downloaded and mounted .pak file via chunk downloader on PC and android. Everything works perfect.
Still don’t seem to find answer for How to update or override .pak file once update is available.
I tried to change version number and file size in manifest but still it loads old PAK file even if new PAK file is available on server.
PLZ help !!!
Thank You

BUMP !!! Any one ?