6.1 to 6.5 is not a major version change. A major version change is 5.0 to 6.0.
Executive Software, makers of Diskeeper, allow current users of their software to download free updates within the same version.
IPSwitch, makers of WS_FTP, provide free updates within versions as well.
Microsoft, makers of such famed titles as Windows and Office, offer a plethora of updates to their software for free.
These are just from the top of my head.
If a defect is found in any tangible product on the market today, it is either recalled or a replacement part or unit is provided for free. This is the law. Software should not be immune to this. If defective code is sold, then it should be fixed for free - end of story. Otherwise, it's just extortion.
