We may see the next version of windows server in the year 2016. Microsoft said Windows Server and System Center will not launch until 2016.
As Microsoft confirmed Windows 10 will launch next year and Windows Server can not be finalized before 2015.
According to TOI news, Microsoft server and cloud team said: Our next preview is planned for the spring of 2015. Windows Server will continue to share the same core technology as Windows and we will continue working together on solutions for our customers. In fact, the next version of System Center Configuration Manager, which delivers support for Windows 10, will ship in a timeframe that aligns with Windows.
Only preview builds will come in the year 2015.
According to Windows Server team of Microsoft We're already busy building the next version of Windows Server and System Center, making it easier to implement hybrid by taking our learnings from running Microsoft Azure at hyperscale to Windows Server and System Center.