This holds true for ALL laptops. Check with the manufacturer before you 'try' to upgrade to Win 8.1. Even if your laptop will support Windows 8 does not mean it will support Windows 8.1.
Thanks for the feedback.
You can always do a clean install of windows 8.1.
I have one ancient laptop, acer 3500 (1.25 gb ram), one old laptop, vaio FZ21Z (4gb ram) and one old netbook, acer D250 (2 gb ram) running Windows 8.1 32bit flawlessly (or with minimal compatibility issues to be more fair).
They all do not "officially" support windows 8 or 8.1