A long-awaited update to Microsoft's Exchange 2003 mail server has been released, with the key enhancement being the ability to push new e-mail directly to mobile devices. The so-called "Direct Push" technology eliminates the need for Microsoft mail servers to notify remote users of new e-mail via text messages. New calendar appointments, contacts and task notifications can also be automatically sent out. The feature is aimed squarely at allowing the software behemoth to compete more evenly with handheld e-mail giant Research In Motion, which sells the popular BlackBerry device line. Another significant new feature included in the update is support for Sender ID, an e-mail authentication protocol that Microsoft is backing as a solution to spam. Microsoft's rivals in this area including offerings such as DomainKeys, which is being pushed by companies like Yahoo and Cisco. Sender ID verifies the Internet address of the server that sent an e-mail against the known IP address of the domain it claimed to come from. This helps to thwart a technique known as "spoofing," in which spammers send e-mail from fake address to avoid being caught.