It is a good idea to keep the contact details of all team members, both the current ones and past members.
It could happen that in the future, the team would need to get help from a previous member in some specific issue. Having the personal contact details of that person would help greatly in such a situation.
The best place for this is to use the app Microsoft Lists, see below.

The list can be used for various purposes, such as:
- In the onboarding flow, the new member gets to insert his or her private contact details
- In the offboarding flow, the parting member can be made to verify that the contact details still are correct
It would also be possible to filter the list and get, e.g. all the previous chairmen, all the members of the team for a certain year, etc.
Having a list of all members of the team like this gives a sense that the team had a life before today, and probably will continue for quite some time in the future, as well. The team had better to work in a structured way today in order for the future team version be able to find relevant information, lead by example (by working smart digitally), build up logic and structure in the team’s digital workplace, and more.