Don't worry I'm sure it will break with Windows 8.1

Amazing how what most would consider a Service Pack almost with 8.1 - it seems to break quite a few things and made a few other unexpected changes.

If you have Windows 8 installed you can update from within the Windows store for free or play the game and download an ISO without a new special key for it but if you try to install on a blank new hard drive you need a new key for 8.1 as your 8.0 key will not work.

Have not confirmed but some say Skype on Windows 8.1 will no longer allow the use of a Hotmail type of account it must now be a Skype account yet on Windows 7 or XP with the latest version of Skype it will still take a Hotmail account. Just odd stuff like that which doesn't seem like much until you run into one of these unexpected issues.