The .tar.gz file of Confluence has been packaged so that the expanded directory name is just "confluence". If two versions of confluence are uncompressed in same directory, the later expansion overwrites the first. I'd prefer the Jira packaging where the expanded directory contains the version number of the expanded software. This would have the advantage of reducing risk of starting to install wrong version and also not accidentally expanding a new version straight over the old one (which I managed to do earlier .