What happens with package when I upgrade rather than removing and reinstalling? What is the real difference between the two? How will the results differ?
Are following two options equal (by package preinst/postint/prerm/postrm steps) ?
apt-get update apt-get remove <packagename> apt-get install <packagename>
apt-get update apt-get install --only-upgrade <packagename>
Can you handle upgrade command specially? Is it possible to make a handler for upgrade instead of deleting and installing?