The Windows 10 May 2021 Update (also known as version 21H1) started rolling out to compatible devices last Tuesday, Microsoft said in a blog post. The operating system update is the latest since the October 2020 update, and includes a few new features like Windows Hello multicamera support and security fixes. (If you're running Windows 7 ($5 at Target), you can still download Windows 10 free to get the May 2021 update and avoid security issues.)

While there are a few useful new features, it seems that Microsoft is using this smaller update cycle to prepare for a larger Windows 10 UI update, reportedly code-named Sun Valley, that will be part of Microsoft's renewed focus on Windows 10 that executives mentioned last year. On Wednesday at the Microsoft Build developer's conference, Microsoft CEO Satya Nadella teased the next update, saying the company is planning "one of the most significant updates of Windows of the past decade," and that Microsoft plans to unveil the new version "very soon."

We won't know exactly what that update includes until it's formally revealed, but we've collected some rumors below. 

Read more: The best antivirus protection of 2021 for Windows 10 

Here's what to know about Windows 10 version 21H1, and what it could mean for the future of the OS. 

What is Windows 10 version 21H1?

Windows 10 version 21H1 is Microsoft's latest update to the OS, and started rolling out on May 18. It's also called the Windows 10 May 2021 update. 

Usually, Microsoft releases a larger feature update in the spring and a smaller one in the fall. But version 21H1, though a spring update, is a more minor update rather than an overhaul. 

Read more: Windows 10 tips: Secret Start menu, taking screenshots and more

What new features does the Windows 10 May 2021 update include?

According to a February Microsoft blog post, new Windows 10 features include:

• Multicamera support for Windows Hello, allowing users to choose an external camera when using high-end displays with integrated cameras.
• Improvements to Windows Defender Application Guard, including optimizing document opening scenario times.
• Improvements to Windows Management Instrumentation (WMI) Group Policy Service (GPSVC) updating, to support remote work. 

"The features we are releasing in this update are focused on the core experiences that customers have told us they're relying on most right now," the post said. "So, we optimized this release to support our customers' most pressing needs." 

According to Digital Trends, the update also includes new icons, updated settings pages and some tweaks to Cortana and the search box experience. 

How can I download the Windows 10 May 2021 update?

The May 2021 update began rolling out on May 18 to select devices, starting with those running Windows 10 version 2004 or later. Not all devices will be offered the update right away, so try to be patient until it reaches yours. There also may be some compatibility issues, according to Microsoft's blog post -- if that happens, Microsoft has a safeguard hold in place and will not offer you the update until the team is confident that you'll have a good update experience.

When the May 2021 update is available to you, you'll be able to download it by going to Settings > Update & Security > Windows Update, and clicking Check for Updates. If available, you'll see Feature update to Windows 10, version 21H1. Click Download and install. 

This marks the first time an H1 (first half of the calendar year) feature update is being delivered using Microsoft's servicing technology. That means it'll arrive the same way that monthly Windows 10 updates do. It's also the same way the October 2020 update was released. If you're already running either Windows 10 version 2004 or version 20H2, it'll be a fast installation process to get the newest update.

What's this bigger Windows 10 update that could be coming next? 

On an October 2020 earnings call, Nadella said that Microsoft is "doubling down" on Windows and PCs, and will continue to innovate. 

This could take the form of a major OS update for Windows 10 later this year that would bring a major design refresh to the UI, according to a report from Windows Central. The update, reportedly code-named Sun Valley, could bring a redesigned Start menu, Action Center and File Explorer, with a more modern look and new features. Sun Valley is expected to be released around the 2021 holiday season, Windows Central says, but that could change. 

Again, at the Microsoft Build conference on May 25, Nadella teased the next Windows 10 update, saying the company is planning "one of the most significant updates of Windows of the past decade," and that Microsoft plans to unveil the new version "very soon."

Another factor: Microsoft said that its Windows 10X OS designed for dual-screen devices like the Surface Duo and the Surface Neo will not come to market this year, as Microsoft originally intended. Instead, Microsoft will build parts of that technology into other parts of Windows and products from the company, the May 18 blog post said.

For more, check out the best three new features in the Windows 10 October 2020 update and six simple security changes all Windows 10 users need to make.