Microsoft on Tuesday released the long-awaited version 5 of Messenger for Mac OS X, which introduces a tabbed client window for connecting to both a corporate and personal IM account. The interface of Messenger 5 has also been polished to better conform to Apple's "brushed metal" theme.

While the Messenger for Mac update largely brings the software up to date with its Windows counterpart, Microsoft's Macintosh Business Unit has designed some features of its own, including new user titles and the unified client approach for business users wishing to additionally connect to public networks.

The corporate tab connects to Microsoft's Office Live Communications Server on the back end, which provides network administrators with additional options to secure instant messaging within a firewall. Microsoft insists that support for the server amounts to more secure corporate communications.

Further additions stemming from Microsoft's horizontal product integration include better integration with Global Address List and the Microsoft Entourage client.

"The big news here is for corporate users," says Jupiter Research senior analyst Joe Wilcox, "and I would predict that will be an ongoing trend coming out of Microsoft's Macintosh Business Unit."

Surveys have shown Mac OS X uptake increasing among businesses, Wilcox noted. "JupiterResearch surveys show Office for Mac usage on par with Mac OS X adoption among very large businesses. MacBU is right to take shift more resources to the corporate market."

Microsoft Messenger for Mac version 5 is available for download via FileForum.