How do I see if the user has disconnected?

I would like to run an sql update statement, every time the user disconnects a session. Correct me if I'm wrong, but I believe I should capture that inside accounting { ... } where the final acctstoptime etc get stored into radacct table. But I don't know how exactly to achieve this. I suppose something like this below, but how do I know if the user actually disconnected? accounting { update request { ... } } Thanks, Mark Sent with [ProtonMail](https://protonmail.com) Secure Email.