1. Free upgrade for Windows 7, 8.1 and Windows 8.1 Phone users Microsoft has promised customers who use these versions of Windows a free upgrade in the first year after the launch of Windows 10. The company also says it will “continue to keep it current for the supported lifetime of the device – at no cost”. It’s promising to deliver new features when they are ready rather than wait for the next major release. 2. Holographic computing Microsoft has…