[Kalcor]

Changing the file would change the CRC, so yes the client will see it doesn't have that CRC, request and download the new version of the file. Since the original CRC is gone from the list, the client will delete the old file.

Edit: Let me be more clear. If the server changes dffs and txds, they should restart the server. The player's game can't be interrupted to download new files, so changing the files requires a complete restart.