Last month Microsoft has released a preview build of Windows 8.1, which is an update for Windows 8 OS. Currently Microsoft has only released preview build and its basicallly for testing, it might have got bugs and errors that’s why we don’t recommend you to use it as your main OS.
If you too waiting for Windows 8.1 RTM build then there is a good news for you, today Microsoft has announced that Windows 8.1 final build will be available by late August for OEM partners, means if you are a MSDN or TechNet user then you can have your hands on by late August.
Microsoft hasn’t announced GA (General Availability) date but they had said that they will keep us updated about Windows 8.1 news in coming weeks. We can expect GA of Windows 8.1 in late October.