If you too planning to upgrade to Windows 8.1 Preview build then there are some things which you must know like :-
- This new update will be available via Windows Store,
- All Windows 8 users will get notification via Windows Store once Windows 8.1 RTM is available, even if you had install Windows 8.1 Preview
- You must have at least 4 GB of free space on your disk,
- Upgrade to Windows 8.1 from Windows 8 is same like Windows 7 to Windows 8,
- If you do not install Windows 8.1 Preview version and straightly go to RTM then all your data, settings, accounts and apps will be there and nothing will be needed to reinstall.
- If you are using Windows RT and updating from Windows 8.1 Preview to Windows 8.1 RTM then you personal files will be there but you need to install all Windows Store apps,
- If you are using Windows 8 Pro then you have to install all Windows Store as well as Windows Desktop apps too, but setting will be there,
Based on above criteria you can decide whether you have to install Preview build or not.