1. One or more computer readable storage media having program instructions stored thereon for updating digital content that, when executed by a processing system, direct the processing system to at least: identify, from a set of files, at least a file that is scheduled to be updated from a present version of the file to a new version of the file as part of an update to the set of files that comprises a set of delta files for updating the file from previous versions of the file to the new version and a complete file for updating the file to the new version; determine if any of the set of delta files can be used to update the file from the present version to the new version; if the set of delta files includes at least a delta file with which to update the file from the present version to the new version, download the delta file; and if none of the set of delta files can be used to update the file from the present version to the new version, download a complete file with which to update the file to the new version.