Some Microsoft employees feel the company's business entanglements with the U.S. military aren't OK, and they want the bosses to know about it.

An open letter to CEO Satya Nadella and Chief Legal Officer Brad Smith from Microsoft Workers 4 Good makes the position of protesting employees clear: "We are a global coalition of Microsoft workers, and we refuse to create technology for warfare and oppression," the letter begins.

Specifically at issue is a $479 million "Integrated Visual Augmentation System" contract that Microsoft entered into back in Nov. 2018. As the letter notes, the intent is for the company to "rapidly develop, test, and manufacture a single platform that soldiers can use to Fight, Rehearse, and Train that provides increased lethality, mobility, and situational awareness" against America's foes.

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According to the letter, to meet the terms of IVAS, as the contract is referred to in shorthand, Microsoft is putting its augmented reality platform, HoloLens, to work. Protesting employees believe this "crossed the line" into weapons development.

"The application of HoloLens within the IVAS system is designed to help people kill," the letter reads. "It will be deployed on the battlefield, and works by turning warfare into a simulated 'video game,' further distancing soldiers from the grim stakes of war and the reality of bloodshed."

These employees take issue with Microsoft's U.S. military commitments, but the bigger problem laid out in the letter is how the company has handled dissent when it comes to those commitments. People who don't want to do military work are given the option of doing something else inside the company.

That doesn't solve anything, the letter says. Shuffling employees around "ignores the problem that workers are not properly informed of the use of their work. There are many engineers who contributed to HoloLens before this contract even existed, believing it would be used to help architects and engineers build buildings and cars, to help teach people how to perform surgery or play the piano, to push the boundaries of gaming, and to connect with the Mars Rover (RIP)."

Employees signing the letter have three demands:

1. Cancel the IVAS contract;2. Cease developing any and all weapons technologies, and draft a public-facing acceptable use policy clarifying this commitment;3. Appoint an independent, external ethics review board with the power to enforce and publicly validate compliance with its acceptable use policy.

A BBC report notes that "at least 50 Microsoft employees" are already on board with the demands. That's only a fraction of a fraction of the company's 130,000-plus workers, to be fair. But there's been a lot of scrutiny in recent years around tech interests partnering up with the U.S. military, and the letter only first surfaced on Friday.

A Microsoft spokesperson told the BBC: "We always appreciate feedback from employees and have many avenues for employee voices to be heard."

Microsoft has been teasing a second-generation HoloLens in recent weeks, and is expected to deliver a first look at the new tech on Sunday at 11:00 a.m. ET, during an event at the annual Mobile World Congress. With a press blitz presumably about to kick off, the timing of this letter and the concerns it raises may put Microsoft on the defensive as its unveiling a brand new product.