Comment 8 for bug 1552373

It used to work with Build 18 - I also find it convenient if I can easily install multiple versions for testing purposes. Copying or renaming the old version before installing the new should work though.

I also noticed that there's no uninstall, because our data files changed so much and the old files are still there. The uninstall will need to write a file that remembers what has been installed.

Innsosetup documentation for [UninstallDelete]:

http://www.jrsoftware.org/ishelp/index.php?topic=uninstcmdline

There seems to be no way to easily call the uninstaller within the installer, so the files to delete will need to be specified in an [InstallDelete] section

http://www.jrsoftware.org/ishelp/index.php?topic=installdeletesection

http://stackoverflow.com/questions/2000296/innosetup-how-to-automatically-uninstall-previous-installed-version