.NET window class names changed

[Gintaras]

is this change is occuring because of change in .Net Framework

Yes.

Is there any solution to overcome this problem except to make changes in classes name all over the scripts?

Now you will have to change something in all macros anyway. Change class names, or remove class names and use only window names. Also you can use wildcard characters in class names. Example:

int w1=win("" "WindowsForms10.Window.8.app*" "" 0x800)
act w1