The “Button-CommandName” property has a new value called “CustomPostback” used for Crystal Reports buttons (controls) added to your application via the Toolbox.
During migration, Crystal Reports buttons you have added to your application may be removed.
Step 1: Manually remove any Crystal Reports buttons that are not removed during migration.
Step 2: Add new Crystal Reports buttons from the Toolbox onto your application pages and configure the button controls appropriately.
Version 5.0 Application Migration