The FName case-preservation bug was fixed quite some time ago.
The issue you may be hitting renaming an asset or folder which differs only by case, is that Windows doesn’t allow you to perform a rename that differs only by case 
The FName case-preservation bug was fixed quite some time ago.
The issue you may be hitting renaming an asset or folder which differs only by case, is that Windows doesn’t allow you to perform a rename that differs only by case