On March 10, Microsoft and Nook Media updated their agreement forged two years ago, according to a new 8-K filing by Barnes & Noble.

Under terms of the amendment, Nook Media is allowed to discontinue distributing the Nook Windows app and to cease work on its Windows Phone app. Ouch.

There seemingly is a replacement app coming for the Nook Windows app, however. It is rather confusingly named "Microsoft Consumer Reader."

This is not a dedicated e-reader, I hear from my sources. (Such a device from Microsoft has been rumored in the past). Instead, I think this is just the name for one of Microsoft's coming e-reading apps.

There seem to be at least two of these apps in the works. The Microsoft Office Reader app , which company officials showed off last year at an employee meeting, will provide users with access to digital content, PDFs and textbooks, according to leaks.

The Xbox team also is believed to be readying a reading app. It's not clear whether this is the same or different from the Office Reader.

In at least one -- and maybe both Readers -- Nook will likely be providing access to some of the digital content.

It's a good bet that a version of this Microsoft Consumer Reader will be available on Windows Phone, too. See this tweet from Nook Customer Care (via @mikebaz).

Update: That tweet seems to have been deleted. Here's what it said:

I asked Microsoft what the "Microsoft Consumer Reader" is and was told by a spokesperson: "We are always looking for ways to evolve and innovate on our app experiences for customers. We have nothing further to share at this time."

Here's exactly what the 8-K says:

"Pursuant to the Amendment, NOOK Media LLC (“NOOK Media”) and Microsoft agreed to co-branding within the Microsoft Consumer Reader for reading content delivered by NOOK Media. The Amendment also provided that subject to certain conditions NOOK Media would be permitted to discontinue distributing the NOOK Windows app and will cooperate in good faith with Microsoft to transition users to the Microsoft Consumer Reader. Microsoft and NOOK Media also agreed to updated revenue sharing to address this possibility. The Amendment also permits NOOK Media to cease efforts with respect to a Windows phone app."

The two companies have also updated their revenue-sharing terms as part of this amendment, but aren't disclosing the particulars.

In April 2012, Microsoft invested $300 million in a new Barnes & Noble subsidiary, initially known as Newco, and later renamed "Nook Media." Nook Media is the part of B&N that made Nook readers and also included the digital/College businesses from Barnes & Noble. The agreement was part of an Android patent-settlement dispute between Microsoft and Barnes & Noble.

At the time of that announcement, it seemed a Nook Windows Phone app was definitely going to figure in a big way.

So it's now looking like Microsoft's $300 million investment is going to end up being all about Nook digital content. And that's about it.