Testers have been putting the new version of the Lync 2013 desktop client and Lync Server 2013 through their paces for a few months.

But there's another Lync product in the family -- an Lync app built specifically for Windows 8 and Windows RT. This is the product to which Microsoft officials previously referred as Lync 2013 MX . This touch-centric, Metrofied ("Windows Storized"?) version of Lync was not released as part of the Office 2013 Customer Preview in July.

But there's now word that this new Lync application will be available in the Windows Store for both Windows 8 and Windows RT as of late October. That's according to a September 20 post on the Lync Team Blog.

Lync is Microsoft's unified communications family of products. Lync offers enterprise instant messaging, VOIP and conferencing. In addition to the desktop client, the server and the new Windows 8/Windows RT Lync app, there also are versions of the Lync client for a variety of smartphone platforms and a browser-based Lync web app.

"The new Lync App ... will be compatible with both Lync Server 2010 and Lync Server 2013," explained the team in the latest blog post. It "is Lync re-imagined for the new Windows Experience."

The coming versions of Lync, as Microsoft officials have indicated, will include Skype federation . Lync 2013 users will be able to see presence, instant message or call anyone on Skype.

Microsoft officials have attempted to distinguish Lync and Skype by describing Lync as Microsoft's inside-the-firewall unified-communications solution, and Skype it's outside the firewall one.

The fact that this new Lync for Windows 8/Windows RT application will be available in the Windows Store in late October 2012 does not mean that Microsoft will release all of the Office 2013 products to manufacturing in October. Microsoft officials are continuing to decline to say when Office 2013 will be released to manufacturing or generally available. (The rumor is November for RTM and February 2013 for general availability/launch.)

Microsoft officials said recently that the final version of Office 2013 Home & Student for Windows RT would be available starting in early November .