Needs and Update
The app completely logs out every time it is closed, meaning you need to re-kid in. However the app retains no account information (eg user ID), nor does it make use of Face ID.
Linked to the above, the app will not populate the user ID and password fields from password manager apps (eg Lastpass) not allow cut and paste from these apps. This means you need to completely be-enter your details manually.
I have found it easier to use the web page to access the portal, due to the missing log-in functionality in the app.
I am very surprised that the app does not appear to have had an update in over three years!