Hi 2010BEBES,
I'm assuming you're asking about what will happen if you buy LR/LM now, and then we release an update (or new versions, etc) later on.
As what we have been doing for a long time now, regardless of whether you buy the download-only or physical (box set) LR/LM,
you can always access upgrades for free -- all you need to do is to download the installer for the new software version, or the updated lesson content files, from your BrillKids Account page. The files you can download from your Account page are always the latest versions, and you can always go back and download them all again as necessary.
For major updates (new software versions and curriculum updates), we always post an announcement about it here in the Forum (and we also send emails), so you will always be informed about these, and what you need to do to get your updates.
Regarding software versions, we always test every new LR/LM version on different Windows systems (32- and 64-bit Windows XP, Vista, and 7, in particular), so you can be sure that LR/LM will always work on the Windows version that you have. You don't need to upgrade your OS to be able to run each new version of Little Reader or Little Math!
I hope this clears up the confusion!