I bought today a MacBook Air and it came without Mavericks ... is it normal ??? Do I have to fear they sold me an old machine ? How do I know if it's the last release of a Macbook or if they sold me a previous generation cpu machine ?
If the machine is shipped before Mavericks is out or existing stock is depleted it won't come with mavericks. This doesn't mean the machine is old it just was made before October 12 or whatever day it was that Mavericks was launched. It's a free upgrade so just sign in to the apps store and download the upgrade.