For WIN7 and WIN8 users, the final version for the FREE Windows 10 upgrade notification invitation has been released to remind users of the July 29th deadline. 

http://www.infoworld.com/article/3097521/microsoft-windows/last-gasp-microsoft-updates-get-windows-10-nagster-kb-3035583-yet-again.html

With nine days to go, Microsoft really, really wants you to claim your free upgrade to Windows 10. Come to think of it, Microsoft has really, really wanted you to upgrade your Windows 7 or 8.1 PC to Windows 10 for more than a year, and backed it with the GWX subsystem — first installed by KB 3035583 in March 2015, 15 months ago.

Now the flirtation includes a yellow exclamation for an icon in the system tray, a popup with a hamburger icon, and a countdown clock that tells you that there’s just 9 days 7 hours 16 minutes and 77 seconds left. You’re given the options of “Decline free offer” and “Upgrade now.” If you decide to upgrade now, you’ll get the old Windows 10.1, version 1511, released last November, build 10586. You will have 31 days to roll back to your original operating system.