When Jetpack CRM receives contacts or other objects to update (via Forms, the API, our Contact Form 7 integration etc.) it can either update all fields (blanking out that which wasn’t passed), or update only passed data. This is often a workflow choice made by users, but this page is here to direct you to the setting.
You can find this setting in Jetpack CRM > CRM Settings > Field Options (/wp-admin/admin.php?page=zerobscrm-plugin-settings&tab=fieldoptions)
The option looks like this:
