Windows 10 Redstone 3 (RS3) Version 1709 (Build 16299.15) is available on the Fast Track for Windows Insiders:
Currently the best way to get it is to Download the Windows 10 Insider Preview .iso build 16292 and perform an in place upgrade.
Then right click the button and select Settings → Update and Security → Windows Insider Program and change your settings to the Fast Track. Although updated RTM installation .isos will likely be available via the Windows 10 Media Creation Tool in a couple of weeks.
Microsoft Edge now can be used as a proper PDF reader. Microsoft have finally supported PDF bookmarks into Microsoft Edge something I've requested since the original release of Windows 10 TH1 (Version 1507):
There is also a tab preview and more support for writing with a stylus:
Also they have put in the ability for full screen viewing: