Delta Patching is a automated process in the Breaking Point Updater that will work out the differential between two updates. This can save time and money and helps uses with slow internet speeds so they don't have to re-download the complete changed files. When the developers add a new weapon, change some configuration they can generate a delta patch and upload it to the server and provide two version numbers.
When you have Delta Patching enabled in the updater, it will check if there is a delta patch present for that file and version on the server to download and apply. If the delta patch fails for some reason then the full file is downloaded normally.
Delta Patches are not always generated by the development team, and sometimes there can be a certain amount of changes where generating a delta patch isn't worth the benefits due to the size of the delta patch.
This process is completely automated, just make sure you have Delta Patching enabled in updater options.