Yes, its applicable to all versions provided you have a genuine copy. But its 28th already and MS has already started rolling out the update files for the upgrade. So its better to go with the official upgrade rather than using the 10240 ISO.
@Sher Your license is connected with hardware. I guess they save some hardware information and then connect it with license. Next time when your PC is online, it will be activated automatically (without user input).
Please note that when you upgrade/change your hardware then probably your license will be invalid.
From what I read, users are getting ISO's with different size/SHA1 when using the microsoft tool. So I think that people who like to do a clean install after doing the upgrade to download the ISO with the following SHA1 sum as it supports both home & pro versions.
Please don't ask for download links. Just search that SHA1 sum in google and you'll get download links.
There are explanations of this; I just read a detailed one a few weeks ago but I can't find it. Small changes (hard drive, adding some RAM, changing a video card) won't trigger activation but changing several things at once may. Additionally, changing the motherboard will trigger it as will, sometimes, flashing BIOS.