Hi Fahad,
We regret for the inconvenience caused.
Regarding “there is some compatibility issue in windows 8.1.”, we would like to inform you that we have provided Windows 8.1 support to our Essential Studio for WinRT (XAML) v11.3.0.33 (Service Pack). If any issue persists, then please share more information about the compatibility issue you have faced along with a screenshot. The information to be provided would be much helpful for us to investigate the reported issue further.
Regarding “i need WinRT XAML, Version=11.2.0.64 unlock key please help me out”, please refer the below mentioned Knowledge Base article link to know about how to generate the respective Syncfusion version(Ex:11.2..x.x) unlock key from Syncfusion support account and generate the unlock for the v11.2.0.25 and use it to unlock the Essential Studio for WinRT (XAML) setup (v11.2.0.64).
http://www.syncfusion.com/support/kb/2326
Please let us know if you need any further assistance on this.
Regards,
Vadivel N