So, that’s it, i’m currently coding a script to update my AppImages, and it works perfectly, first the script lists all the AppImage files in my ~/Apps folder and then ask me if a want to update an app.
And if i select an app, it will execute “AppImageUpdater” and get the job done, even it removes the old App.
BUT, what i really want is in fact, showing JUST the application with available updates, how can i do this? thanks 
AppImageUpdate checks whether a newer version is available, and immediately updates if there is. But it does not hurt to run AppImageUpdate if there is no newer version available.
If you really just want to check if there is a newer version available, you would have to change AppImageUpdate and the underlying zsync-curl.
So, in order to modify AppImageUpdate and the underlying zsync-curl i need to do some changes on this function under AppImageUpdate.AppDir/usr/bin/appimageupdate ?
or do i need to change every $TYPE function in order to get what i want?
You would need to edit the C source code of zsync-curl too.
