If you use IM on your PocketPC you will need to upgrade. The folks at Pocket PC Thoughts shed the light on this upgrade.
"As part of the MSN® Messenger Update, which ensures that our customers have the latest security and privacy protections when using the .NET Messenger Service, all .NET Messenger Service clients, including Windows Mobile-based Pocket PCs and Pocket PC Phone Editions, are required to update to compliant versions of MSN Messenger client service software by October 15, 2003. Pocket PC and Pocket PC Phone Edition customers should update their MSN Messenger clients by downloading the following updates to their devices prior to October 15, 2003 to prevent any MSN Messenger service interruptions." The bad news is that it's not an XIP Flash update, but the good news is that it appears to only take up 227 KB of RAM on a Pocket PC 2002 device, and 150 KB on a Windows Mobile 2003. These figures were just pulled out of the air after Janak and I did the install, so don't take them as gospel.
[Pocket PC Thoughts]