An outdated keychain is a huge challenge when not every key has been identified. Usually, you only deal with the ones you carry. And memory is crucial when using them. Now, in your case, managing a temporary tenant, it’s quite a challenge.

Perhaps, in the future, with the boom and ultimate triumph of home automation, QR is the solution. Although, to be honest, it doesn’t give me a full sense of security.

Greetings.