Windows 95 evolved through the years into Windows 98 and Windows ME. Windows ME was the last in the line of the Windows 3.x-based operating systems from Microsoft. Windows underwent a parallel 32-bit evolutionary path, where Windows NT 3.1 was released in 1993. Windows NT (for New Technology) was a native 32-bit operating system with a new driver model, was unicode-based, and provided for true separation between applications. Windows NT also supported 16-bit applications in an NTVDM, but it did not support VxD based drivers. Windows 95 was supposed to be released before 1993 as the predecessor to Windows NT. The idea was to promote the development of 32-bit applications with backward compatibility – leading the way for more successful NT release. After multiple delays, Windows 95 was released without unicode and used the VxD driver model. Windows NT 3.1 evolved to Windows NT 3.5, 3.51 and then 4.0 when it finally shared a similar interface with its Windows 9x desktop counterpart and included a Start button. The evolution continued with Windows 2000, Windows XP, Windows Vista, then Windows 7. Windows XP and higher were also made available in 64-bit modes. Windows server products branched off with the introduction of Windows Server 2003 (available in 32-bit and 64-bit IA64 or x64), then Windows Server 2008 and then Windows Server 2008 R2. Windows 2000 and XP shared the same basic GUI although XP introduced Visual Styles. With Windows 98, the Active Desktop theme was introduced, allowing an HTML approach for the desktop, but this feature was coldly received by customers, who frequently disabled it. At the end, Windows Vista definitively discontinued it, but put a new SideBar on the desktop.