Yes, there’s a dark theme and new emojis, but there are a lot more than aesthetic changes in the latest Windows 10 build released to Fast Ring Insiders Wednesday. In Build 14316, Microsoft is making available for preview a number of features slated for this summer’s Anniversary Update.

Let’s start with perhaps the most interesting for developers: the ability to use Bash on Ubuntu in Windows, announced at last week’s Build conference. To try it out, just make sure you’re in Developer Mode, enable the Windows Subsystem for Linux in Windows Features, and type ‘bash’ at the command prompt. Get more details here. Microsoft emphasizes that this is a developer tool, not a server platform, and it’s in beta, so user beware.

Virtual assistant Cortana has gained some ability to work across devices in the new build. She can now send a notification to your PC when your phone or tablet is running low on battery, use geo-location to find a lost phone, and share maps and directions across devices.

In Microsoft Edge, PinIt Button and OneNote Clipper are now available as extensions alongside the extensions Insiders have already been playing with, including Reddit Enhancement Suite and Microsoft Translator.

The Skype UWP Preview app–which Microsoft is touting as a cleaner, streamlined version of the current Skype app–is also now available to Insiders. It only works in PCs for now, but Microsoft promises a mobile version is coming soon.

One important caveat for developers about this new build: It causes the Visual Studio emulator for Windows 10 Mobile and HoloLens to fail. So if you need the emulator to build apps, Microsoft suggests moving to the Slow ring and sitting this one out.