At the moment, it is not possible to change the email address for your DuoxMe account directly from the app.
To update your email address, follow these steps:
1. Delete the account with the email address you no longer wish to use from the app in Settings > General tab > My account > Delete account.
2. Register your new email address by creating a new account in the app.
3. Log in with your new email address and tap Add video door entry system to pair your Fermax terminal with your new account.