Windows 7: Anytime upgrade

I have an OEM manufacturer-supplied version of Win 7 Home Premium 32-bit which I've upgraded to Ultimate with an Anytime Upgrade key.

I'm going to buy Home Premium 64-bit.

I've read a few posts which suggest this - and the MS site - but I just want to confirm that the Anytime Upgrade key will still upgrade the 64-bit version once I've performed a clean install.

The MS site says:
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Can I upgrade both 32-bit versions and 64-bit versions of Windows 7 with Windows Anytime Upgrade?



Yes, you can use Windows Anytime Upgrade to upgrade a 32-bit version to a 32-bit version or from a 64-bit version to a 64-bit version of Windows 7. However, Windows Anytime Upgrade can't upgrade a 32-bit version to a 64-bit version of Windows 7 or a 64-bit version to a 32-bit version of Windows 7.
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Does this mean I can install dual boot and have both upgraded to Ultimate, or do I need to uninstall (or reinstall to downgrade) the 32-bit version first?

Legally, you can only have one or the other installed at the same time.

tw33k is right, in order to have both 32bit & 64bit versions installed on a dual boot setup you would need to purchase the Anytime upgrade for both versions.

Thanks both, legal situation understood
Could you confirm that the Anytime Upgrade key will upgrade the 64-bit version once I've performed a clean install..?
I don't want to buy 64-bit Home Premium then find that the upgrade to Ultimate doesn't work.

You are correct. The Anytime Upgrade will work on 64-bit.