Microsoft quietly rolled out this week a cumulative update for its Lync 2013 client that includes support for two-factor authentication.

Believe it or not, Lync client didn't have two-factor authentication support before now. And after this week's rollout, the Microsoft Lync client is the only client for Lync that does offer two-factor authentication, a company spokesperson told me. (There were some tools in place for managing Lync Security and authentication before now, but not two-factor authentication in the client, the spokesperson added.)

Lync is Microsoft's unfied messaging product. It includes business instant-messaging, presence, VOIP and online meeting functionality and is the business complement to Skype.

In April 2013, Microsoft announced it would be making available "two-step verification" across all products and services accessible via a Microsoft Account . This included Windows, Windows Phone, Xbox, Outlook.com, SkyDrive, Office and more, officials said. Two-step verification is, basically, two-factor authentication.

Two-factor authentication is aimed at reducing the likelihood of online identity theft, phishing and other scams because the victim's password would no longer be enough to give a thief access to their information. Apple, PayPal, Google, Facebook and other vendors already have implemented two-factor authentication.

Back to Lync. Users need the July cumulative update for Lync Server 2013 to enable the two-factor authentication and other client feature enhancements, which include embedded images, meetings view, IM mute and Q&A manager.

Last month, Microsoft made a number of updates to Lync to improve the Lync Meeting experience. Among those enhancements were the ability to "turn any conversation on a Windows Phone, iPhone or iPad into a Lync meeting," the ability to view Lync meeting content from Windows Phones and iPhones; the ability to see Outlook meeting schedules and join Lync Meetings from directly inside the Lync client; and the ability to control meeting interactions with IM mute and Q&A manager.

Those new meeting capabilities were updated for Office 365 and Lync Online. But on-premises Lync users couldn't take advantage of them until this week, by applying the July Cumulative Update for Lync Server 2013.

Microsoft's guidelines for planning for and deploying two-factor authentication with Lync are here. One caveat worth calling out from Microsoft:

"Customers who have deployed two-factor authentication for Microsoft Exchange may find that certain features in the Lync client are unavailable. This is currently by design, as the Lync client does not support two-factor authentication for features that are dependent on Exchange integration."