No aspect of VSys is open source, but the vast majority of it can be customized by defining your own fields and modifying existing ones, creating custom application forms for data entry, and the use of the Interactive File Importer for bringing data in from other sources. While you can’t modify the underlying programming of VSys, we always get the best feature ideas from our customers. If there’s something you’re looking for that’s not there, tell us, and if we think it would be broadly applicable, it will likely make its way into a future update.