Sources say Microsoft is testing a version of Outlook for Windows RT, the flavor of Windows that runs on Redmond's ARM-based Surface RT tablets, but whether it will ever see the light of day is another matter.

Well-connected Microsoft watcher Mary Jo Foley reports that no less than three of her insider contacts have confirmed that an ARM version of Outlook exists, but that its future is clouded by internal politics.

All Windows RT devices, including Surface, come preloaded with a copy of Office 2013 Home & Student RT. But that bundle includes only Word, Excel, PowerPoint, and OneNote; Outlook ships only with the Home & Business edition and above.

That leaves Windows RT users with no way to do serious business messaging and collaboration on their devices. The built-in Mail, People, and Calendar apps for Windows RT offer only basic functionality – less than what you get with some smartphones – and there's nothing much in the Windows Store to improve on them. Really, the best solution is to use webmail.

According to Foley's sources, however, while some within Microsoft would like to rectify that situation, others would rather keep the current Windows RT bundle the way it is. Some of those apparently even think the correct solution would be to rename Windows RT's existing Mail app to Outlook – gotta work that branding!

But even if the camp that's pushing for a native ARM version of the full Outlook client wins the day, questions remain. Most notably, just how would Windows RT users get their hands on it?

Unless Microsoft has built Outlook RT as a Windows Store app – and while there's no word on whether it has, it seems unlikely, given the Windows Store's strict UI constraints – there would be no obvious way to load it onto current Windows RT devices, because Windows RT only allows Windows Store apps to be installed.

It's possible that Microsoft could release Outlook RT with a special kind of installer that loads it onto devices using some secret trick, but that's exactly the kind of thing it seems intent on preventing, as demonstrated by its efforts to shut down the Surface jailbreaking hack.

It seems more likely that Microsoft might be readying Outlook for inclusion with a future generation of Windows RT devices – one that has a more business-oriented bent. Call them Surface RT Plus, if you will, or Surface RT Home & Business Edition.

Or, as Foley's sources stressed, it could all be for naught, and Outlook RT will never be seen outside of Redmond.

Microsoft hasn't sold as many Surface RT devices as it had hoped, and lack of Outlook is hardly Windows RT's only deficiency. With Surface Pro due to arrive on February 9, Microsoft's best bet might be to send business customers that way. If that is the plan, releasing a version of Outlook for Windows RT would only muddy the waters – and it would probably add very little to Redmond's bottom line, to boot. ®