Microsoft (NASDAQ:MSFT) CEO Satya Nadella has not been shy about making changes to his company. 

Since being named to the post in February 2014 he has delivered some major amendments to how the technology giant operates. This included realigning his executive team; laying off thousands of workers; bringing a free version of Office to Android devices, as well as Apple's (NASDAQ:AAPL) iPhones and iPads; and announcing Windows 10, a radical update to the company's signature product.

Now, after making more major changes to his executive team including the departure of former Nokia CEO Stephen Elop, Nadella has sent a letter to his employees, which was published by GeekWire, in which he outlined his vision for the future. 

Nadella has made some major changes since taking over. Source: Microsoft.

Microsoft is no longer a closed system
One thing Nadella has strongly pushed is the idea that Microsoft software and services should not be limited to Windows users. He reiterated that in the letter and essentially completely divorced himself from the company's closed-off, walled-in policies of the past.

First, we will reinvent productivity services for digital work that span all devices. We will also extend our experience footprint by building more business process experiences, integrated into content authoring and consumption, communication and collaboration tools. 

Since Windows has in many cases been usurped by Android and iOS, Microsoft will bring services such as Outlook, Office, and Skype to whatever platforms people are using.

It's all on the cloud
Microsoft has been among the companies leading the push to the cloud; Nadella not only expects that to continue, he cited the cloud as being a key driver for the company.

All these experiences will be powered by our cloud platform -- a cloud that provides our customers faster time to value, improved agility and cost reduction, and solutions that differentiate their business.

The CEO also expects the cloud model to help the company attract partners and developers, something that should expand the reach of Microsoft's offerings. Essentially this will be a two-way street, helping the company by expanding its services, but also allowing it to provide tools for any potential products created by partners. 

We'll further provide a powerful extensibility model that is attractive to third-party developers and enterprises. This in turn enables us to attract applications to our cloud platform and attach our differentiated capabilities such as identity management, rich data management, machine learning and advanced analytics.

Nadella and his company have been trying to make it worth developers' time to create products for the company. Moving everything to the cloud and offering device/operating system-agnostic products should make that task easier.

It's about the customer
Microsoft has never been the most customer-friendly company -- for years it had a near-monopoly with Windows and did not need to be. Nadella knows those days have long since passed, and he intends to put customers first, saying in the letter he wants his employees to become "customer-obsessed."

We will learn about our customers and their businesses with a beginner's mind and then bring solutions that meet their needs. We will be insatiable in our desire to learn from the outside and bring that knowledge into Microsoft, while still innovating to surprise and delight our users.

That sounds like an easy change, but it's one that Nadella's predecessor, Steve Ballmer, failed to embrace long after it had become obvious that consumers now had options. 

More change is coming
Nadella sees major opportunity for his company, but he also knows growth won't come without pain. He closed the letter in way meant to both inspire his employees and warn them that the tough choices are not in the past.

I believe that culture is not static. It evolves every day based on the behaviors of everyone in the organization. We are in an incredible position to seize new growth this year. We will need to innovate in new areas, execute against our plans, make some tough choices in areas where things are not working and solve hard problems in ways that drive customer value. I really do believe that we can achieve magical things when we come together as one team and focus. I'm looking forward to what we can achieve together in FY16.

That's a difficult message to deliver because some of those "tough choices" undoubtedly involve changes or cuts to employees. Nadella has made it clear from his words and actions that he intends to transform his company, and making those changes will result in some people not making it to the final destination.

It's not an easy path, but Nadella is leading the way, and his expectations seem very clear.