Please refer to http://blog.parallels.com/blog/2015/11/03/windows-10-in-parallels-desktop-11/ which mentions the prerequisites for Windows 10 on Parallels Desktop. Considering that you do meet up the requirements, you will not face any issues running Windows 10 onParallels Desktop 11 . Also, refer the same blog for steps to upgrade Windows 8.1 to Windows 10.
