⟩ Which devices are supported by Microsoft to be used with OMA?
Device support for Outlook Mobile Access (OMA) Browse is dictated by the Device Update package installed on the Exchange 2003 server. When you run Exchange 2003 Setup today, the DU2 package is silently installed as part of the installation.
Approximately, every 6 months, new Device Update packages are released. This will add support for more devices to your Exchange server.
The current Device Update package is DU4. The full list of devices and which DU package they are included in is available here.