Apparently Microsoft is offering users a free upgrade (for 1 year) to its soon to be released Windows 10 operating system. I am unclear whether users have to pay for the upgrade after the first year or whether it remains free for early adopters. Microsoft jumped from Windows 8.1 to Windows 10. There has been a low uptake of Windows 8 and 8.1.
See http://www.bbc.co.uk/news/technology-30924022 .