By default, Tasks, Appointments, Journal Entries, and Contacts hide the controls in the Outlook user interface used for linking related contacts. When you enable this setting, the linking controls appear in Outlook. You might choose to enable this setting if your users rely on contact linking - for example, to track partners who attend appointments together or to track ways in which contacts are related to each other.
| Registry Hive | HKEY_CURRENT_USER |
| Registry Path | software\policies\microsoft\office\16.0\outlook\preferences |
| Value Name | showcontactfieldobsolete |
| Value Type | REG_DWORD |
| Enabled Value | 1 |
| Disabled Value | 0 |