In order to take advantage of the free upgrade, users will need to be running the latest version of either Windows 7 Service Pack 1 or Windows 8.1. Beyond that, users will need at least a 1 GHz processor or System-on-a-Chip, a display with a resolution of 1024x600 pixels, and a graphics card that supports DirectX 9 or later with a Windows Display Driver Model 1.0 driver. Users of 32-bit Windows 10 will need 1 GB of RAM and 16 GB of free hard drive space, while 64-bit users will need 2 GB of RAM and 20 GB of available storage space.
If those requirements sound familiar, that's because they're the same base requirements Microsoft currently has posted for Windows 7. It's worth noting that not every Windows 7 or 8.1 device will be able to make the upgrade even if they meet those requirements. Microsoft makes clear in its support notification that some devices that meet the minimum specification won't be compatible because of issues with "firmware support, application compatibility and feature support."
Users who want to make sure that their device is compatible can use the Get Windows 10 app's "Check my PC" feature to make sure that they're eligible for an upgrade.
When a user begins to install the update, the Get Windows 10 app will scan their device for any apps that are known to be incompatible with the update and provide a user with a list of known issues. In order to continue installing, people will have to uninstall those apps that cause problems.
In a similar vein, the installer may also remove some applications that came pre-installed from a device's manufacturer. It's not clear exactly what those will be, but given the problems that Lenovo users encountered with the Superfish advertising application earlier this year, Microsoft may be using this upgrade as an opportunity to clean devices of shady apps.
The installer will also detect a user's anti-virus and anti-malware software, uninstall it, and then re-install the latest version of it after the update with the user's previous settings applied. In the event their current anti-malware subscription has expired, they will have Microsoft's Windows Defender protection suite enabled after the upgrade.
Windows 7 users who need their Solitaire and Minesweeper fixes will have to download the new Microsoft Solitaire Collection and Microsoft Minesweeper games from the Windows Store. The Windows 10 update will delete the games that have traditionally come built in with Microsoft's operating system.
Microsoft is also doing away with Windows Media Center in Windows 10, which means that anyone with a Windows 7 or Windows 8 PC will have that software removed when they upgrade. Microsoft is also doing away with built-in DVD playback software, so users will have to get their own if they want to watch a movie or TV show on a physical disc.
Not every device will be compatible with the latest features available in the update, either. In order to use the facial or iris recognition features of Windows Hello, users will need a specialized illuminated infrared camera. (Surprisingly, neither the Surface 3 nor the Surface Pro 3 features such a camera.) Cortana, meanwhile, only works in the U.S., U.K., China, France, Italy, Germany and Spain.
Overall, the low barrier to entry seems tailor-made to help Microsoft meet its goal of having one billion devices running Windows 10 by the end of the company's 2018 fiscal year. Getting as many devices as possible on Windows 10 is important, since Microsoft is pushing developers to create new applications for the Universal Windows App Platform and sell them through the Windows Store. In order to motivate developers, Microsoft will need plenty of Windows 10 users.