looking for a way to see when Fortitoken has been used for the last time

Hello, I am trying to find a way to see when a vpn user has logged in for the last time.

Issue is, that one of my customers has issued 200+ soft tokens and sometimes users don't use the vpn for months. The customer wants to reassign unused tokens and disable users that haven't used the vpn solution for let's say 3 months.

Is there a way (in FortiOS 5.4.x) to accomplish this?

Thanks in advance,

Ralph Willemsen

Arnhem, Netherlands