The latest version of Spread ASP.NET is Spread Studio 8 and can refer to the following link for new version:- http://spread.grapecity.com/Downloads/Download/?productID=1
Up-gradation is not a complex process. Please follow the steps below for upgrading your application from Spread version 5 to Spread version 8.
1) Un-install the older Spread version 5.
2) Install new Spread Studio 8
3) Open existing application.
4) Delete all Spread references from Project's "Solution Explorer" References folder.
5) Delete licenses.licx file and also web.config file as well.
6) Add a new form and drag drop Spread of new version into the form's design mode.
7) This will add references of Spread Studio 8 into your project and also will create web.config file.
8) Open all existing forms and check Spread reference version on top of the form and replace it as per new form.
9) Rebuild the application and run it.
Hope it helps. Let us know if you face any issues.