Historically, when Windows upgraded, it carried all its baggage with it from the previous install (for better or for worse). Windows 10, however, seems to have deviated from this. Now if an application is deemed incompatible with the build being upgraded to, the application will simply not be present in the post-upgrade operating system. Windows should warn the user of this prior to upgrade and, if ignored, report this in a report file at C:\Windows\Panther named miglog.xml that the application was not migrated forward.
When first faced with this news, it is logical to assume that this is a complete disaster and poor choice. However, consider the upgrade process as a guardian of sorts. After the upgrade, Microsoft would like you to be able to log in to the system and actually use it to do work. If an application is going to break the installation, why migrate...