Installer does not uninstall current version before installing new one

[Neustradamus]

Dear @TaskExplorer team, @DavidXanatos,

I have found a bug.

Bug Description

The installer does not uninstall the previous version before to install the new one.

Expected Behaviour

The installer uninstalls the previous version before to install the new one.

Steps to Reproduce

Install an old version and try to install a new version.