Earlier today, Microsoft released a new Office Insider build for Macs, and later, another for Android. It seems as though the Office team isn't done just yet, as there's now an update for the Office Mobile apps for Windows 10.
The December update brings the version number to 17.7668, and it focuses on improvements to Excel and OneNote:
Lasso select now at your fingertips with Excel Mobile Tap the Surface pen button to use Lasso Select on ink without visiting the ribbon.
Select and move objects with greater ease in Excel Mobile Use your Surface pen to resize, rotate, move handles on objects and more.
Open more files with Excel Mobile Now you can open files that contain form controls and Scenario Manager on your device.
Add multiple Microsoft accounts to OneNote You can now add all of your favorite notebooks to OneNote, even if the notebooks were created by using different Microsoft accounts.
Undo easily with OneNote Minds can change anytime! Use the undo button to rewrite and undo your note-taking history.
Microsoft is continuing to make its Office UWP apps more and more powerful, adding new features every month. If you're not an Insider, you'll probably see these features within a couple weeks.
If you want to sign up to be an Office Insider on Windows 10, you'll need to be running a Windows 10 Insider Preview build on your PC or phone, and have an Office 365 subscription. You can download or update your apps from the following links:
