Hello Tuan,
I wanna upgrade to a new version,
but i modified some "View" files. My changes will be lost?
i can upload these files after upgrade, or is better modify again?
Yes. It will be lost. It is better to modify it again after upgrade. However, you can first try to replace the new files with your modified files first, then you can check, if it still works well, then you don't have to modify it again
