We are working on this project for a client that requires to keep track of contacts and of any changes that are made to it. In order to achieve this, we were able to connect Vtiger to the FOE so when any edits are made to the FOE, the contact stored in Vtiger will be updated with the new information. This helps to keep the most up to date information about a contact, that being a client. In addition, this works when creating a new contact on FOE. When a contact is added on the FOE, the two of them will be linked for future events. So the next time you load the FOE for that specific client, it will show you all the related contacts that come with the client, that being an Espouse, Son, Daughter, Friend, ETC.
This is a good functionality for people who want to connect Vtiger to an App and has to update them on the go. Finally, this is for the ones have to add related contacts on the Go and see the changes being applied on Vtiger. This is a function that allows you to keep up with contacts, that being edited them, add more, or even display related contacts altogether.