Microsoft released the preview of the March update for OneNote on Windows 10 today, bringing the version number to 17.9126.2036. The update is available for Insiders in the Fast ring that chose the Skip Ahead option - as regular Fast ring app updates are frozen due to being so close to RTM - and Office Insiders.
Most of the new features seem to focus on cross-platform functionality. For example, you can choose a customized set of pens and highlighters to use, and that set will be available across all of your Windows 10 PC and iOS devices. It also syncs across the entire Office suite, including not only OneNote, but Word, Excel, and PowerPoint. Presumably, this feature will be coming to Android soon as well.
The notes also say that you can move notebooks from local storage into OneDrive, which will allow you to access your notes from anywhere. Your recent notebooks also sync across devices now, so if you use something on Windows, it will be suggested to you on other devices.
Finally, you'll receive notifications whenever someone has edited your shared notebooks. This will be a useful feature if you do a lot of collaboration, as it will help you to track who is working on what, and when they're doing it.
The update is available for Insiders now, and will likely reach the general public within a couple of weeks.