Current available versions:
Windows 10 Mobile
Windows Odyssey
Windows Neptune
Windows NT 4.0
Windows NT 3.5
Windows Server 2019
Windows Server 2016
Windows Server 2008
Windows Server 2003
Windows 1.0
Windows RT 8.1
Windows RT
Windows Phone 8.1
Windows Phone 8
Windows Phone 7
Windows Mobile 6.0
Windows Mobile 2003
Pocket PC 2002
Pocket PC 2000
Windows Embedded Automotive
Windows Embedded Compact 2013
Windows Embedded Compact 7
Windows CE 1.0

Taken Versions:
Windows 10
Windows 8.1
Windows 8
Windows 7
Windows XP
Windows Vista
Windows 2000
WIndows 98
Windows 95
Windows ME
MS-DOS

Microsoft[www.microsoft.com]