If you are a Windows Mobile user who connects to a PC, first make sure your PC is up-to-date. (see http://www.microsoft.com/dst2007 for more details). For Windows XP SP2 and Windows Server 2003, the update has already been deployed using Automatic Updates and should be installed, if you have Automatic Updates enabled. If you want to verify that it is installed, you can visit Windows Update and make sure all High Priority items are installed. For all products not currently in mainstream support, see KB 914387 for steps on manually updating your PC.

Step-By-Step
If you are connecting to a PC, first make sure to update your PC by installing the 2007 time zone update for Microsoft Windows operating systems. This will update the time zone definitions on your PC. (If you use Microsoft Outlook to synchronize your calendar, you should also download and run the Outlook Time Zone Update Tool.)

Next, check to make sure you have the latest version of ActiveSync (ActiveSync 4.5) and then connect your Windows Mobile device to your PC and download and run the Daylight Saving Time 2007 Update Tool for Windows Mobile. If you are using Windows Mobile 2003 or Windows Mobile 2003 Second Edition you will need to follow different instructions.

Non-PC Users
If you do not connect your device to a PC, there is a special update file (CAB) available for you. There are a number of ways to install a CAB file; we'll walk you through one popular method:

Using the Internet Explorer Mobile browser on your device, go to http://www.microsoft.com/windowsmobile/ and download the Daylight Saving Time 2007 Update. This file will install the update directly on your device. Just click on the file you downloaded to install the update. If you are unable to access the link on your device, open Internet Explorer on your PC and click here to start the download process. After downloading the file, attach it to an e-mail and send it to an account you can access on your device.

On your device, open the e-mail and save the attached file; on some devices, you may need to synchronize your e-mail a second time to download the attached file. Once the file is downloaded to your device, click on it to install the update. After you install the update, your device may automatically restart to ensure that the update is complete.

Pocket PC DST Tips
On some Windows Mobile devices, the DST change may fail to initialize even after applying the update. If you run into this problem, there are a few troubleshooting steps you can take.

The first thing to try is changing your time zone settings. After installing the update, change your default time zone to some other zone than the one you are in; any zone will do so long as it is different from your current default. (If you are on Eastern time, try setting to Pacific or Central, for instance.)

To change time zone settings on your Pocket PC, tap Start, choose Settings and from the System tab menu select Clock & Alarms.

Select a time zone from the drop down menu for Home settings and then save your settings by tapping OK.

Once you've saved the settings, change them back to the correct time zone value. This should correct your problem and enable the update to become active.