I'm considering upgrade from Postgres 8.3.3 to 8.4.2 on my machine (it has Windows Vista). Windows Installer (one click installer) for Postgres 8.4.2 that can be downloaded from enterprisedb.com offers only fresh install (it does not recognizes my current installation of v8.3.3). Is it possible to upgrade with all existing databases converted and visible (automatically migrated?) in new version just after upgrade? Or I have to do something more - backup/restore all my databases manually?