My Firefox is 49.0.1
My Windows is 10 version 1607 for x64-based systems. I get automatic "updates" to Windows 10 fairly frequently. The most recent was only a few days ago.
Windows 2000 has been "dead" for quite some time, and this coming Oct 31st is said to be the official "dead date" for Windows 7 and Windows 8.1, whatever that means.
