The first backup is always full, then are sent differences/increases. The Full copy every x option - if the user selects this option and set e.g. that full backup is to be performed every 7, the seventh performance of the backup will be sent the full version of the changed file, the files that have not changed will not be sent, Version limit - it allows to reduce or increase the amount of data stored on the server by changing a number of file versions that will be stored. If the file is changed daily and backup is performed every day, then each copy is added to the next version of the file, Days limit - it means that after its expiration are deleted all versions except the last full version. You have to remember that files are versioned, not data packages.