Some versions of QAS do not have the password expiry warning enabled. This feature pops up a warning at user login that the user's password is about to expire in however many days. This window will start popping up at each login, starting two weeks (by default) before the user's password will expire.
This was disabled by default due to interference with other login pop-ups, notably the prompt to create a mobile account. If both alerts came up at the same time, the login process would hang indefinitely as one modal window was blocked by another.
If you are not using mobile accounts and wish to enable the password expiry warning, edit the /etc/authorization file and insert the pwexpire line between the "VASMechanism:userpolicy,privileged" and "HomeDirMechanism:login,privileged" lines as below