Microsoft has now released Windows 10 Redstone 2 Build 15055 to Insiders in Fast ring. You can read what the build brings in terms of changes, new features, fixes and also known issues by clicking here.
Third party ISO images of the Build 15055 are now available and you can download them to upgrade your Windows. You can refer to our tutorials on how to create bootable USB drive and how to do a fresh Windows 10 installation.
You can download official ESD & UUP files for Windows 10 Build 15055 and can convert it to ISO as detailed in our updated step by step tutorial here.