Installer - Update Options

## Installer - Update Options |

| Please see the help topic on updates for a general discussion on how generated installers handle installations when an earlier version has already been installed.

| Every install4j project has an application ID. When you create a new project, the application ID is calculated. The ID is displayed on this tab. If you have to change the ID, you can use the [Regenerate ID] button. You can also change the ID manually if the `manually edit ID` check box is checked. You should only change the ID if you want to change the identity if your project. The application ID ensures that later versions of your application will be able to find and recognize earlier installations.

| install4j offers two types of installers: Regular installer This generates standalone installer. The following options related to updates are available for regular installers: Detect previous installation directory If a previous installation can be detected on the computer, the installer will suggest the directory of that previous installation. In that case, the "Welcome" screen will ask the user if the previous installation should be updated. This question can be suppressed in the configuration of the "Welcome" screen. Add-on installer This generates an installer that can only be installed on top of an installation of a certain installation. An add-on installer doesn't have a separate uninstaller. This is useful to distribute patches and enhancements. If the add-on installer type is selected, you have to enter an application ID for the base application in the text field below. With the [...] chooser button, you can select an install4j project file from your file system, and extract its application ID.