"When I was playing with the xda II on weekend I"ve tested more or less every functionality and application. One of them was for sure MSN Messenger, it notifies you to imediatly download an updated messenger update. However, if you follow the links provided there you get the following information:
MSN Messenger Security Update for Windows Mobile-based Pocket PCs and Smartphones
The MSN Messenger Security Update is part of Microsoft"s Trustworthy Computing initiative, which aims to provide customers with improved security and greater privacy protection. As part of this update, all .NET Messenger Service clients will be required to upgrade to compliant versions of Messenger service client software by October 15, 2003. Microsoft is developing updates for Windows Mobile-based Pocket PCs and Smartphones."