After the release of Windows 10 Redstone 3 build 16184 last week, Windows Insiders in the fast ring got their next preview build 16188 for PC today along with Mobile build 15210. This PC build includes a lot many new features and enhancements that you want to try.

Before going to download the new preview build from Redstone 3 development branch, don't forget to checkout the 'Known Issues'.

When you try to open any office file documents created with an earlier version of Office applications like Word 95, Word 6.0 or Word 2, the file will open in 'Protected View' by default and the editing functions will be disabled.

Though it is not recommended, but if you face such issue and still want to open the document for editing, you can follow the steps mentioned here.