Research on adding new version of form template to server

When updating the form templates in server, what actually happens?
In the server:

• is the old form template got replaced?
• creating another form template? If so, how to differentiate the versions?
  In the device:
• will user get a notification on the device that a new version of form template is available?
• If user chooses to sync the new version of the form template, what happens to the old form template?
• If user decides to remove the old version of form template, will it cause any issue when there are incomplete form data/complete form data in old version (not being synced) to the server?