Version 1.5.0 introduces the option of having users enter their own password (if identity borrowing is not enabled).
In the Messaging tab, you can deactivate identity borrowing (uncheck the box).
In this case, each user will have to enter their Exchange password to retrieve their information.
In order to encrypt Exchange passwords (if identity borrowing is not enabled), it is essential to have an extended version of "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy", which can be found here :
http://www.oracle.com/technetwork/java/javase/downloads/jce8-download-2133166.html
Les 2 fichiers jar présents dans le zip téléchargés doivent être positionnés dans <java-home>/lib/security
(save the 2 files already present if this is the case)