As others have said, my understanding is that deltas within a major release are upgrades. In fact I have upgraded from 6.3 to 6.4 and now 6.4 to 6.5, but had to

As others have said, my understanding is that deltas within a major release are upgrades. In fact I have upgraded from 6.3 to 6.4 and now 6.4 to 6.5, but had to re-install this machine to enable hard drive encryption. The 6.3 -> 6.4 and 6.4 -> 6.5 updates arrived simply as software updates using the usual process just involving the download 340Mb of files. I gather the 6.x designation relates to updating the installer and packages available on the release DVDs I think you are referring to 5 to 6 and ultimately 6 to 7. Major versions.