Installing FileMaker Server
In Windows (FileMaker Server only) or macOS (FileMaker Server only), the FileMaker Server installer can be used for new installations and also for upgrading an existing installation from an earlier version. (See the FileMaker Server Release Notes for the versions you can upgrade from.) During an upgrade, the installer detects the previous version that is installed, and displays the appropriate screens.
In addition, the installer preserves most user data and configuration. Settings are saved automatically, and you don’t need to uninstall the current installation. The installer finds your existing databases, configuration files, SSL certificate, logs, and other files; it then installs or replaces new executables and libraries while transitioning your files to the new version. This process converts your preference files to an updated format without making changing to the database files.
See Upgrading FileMaker Server on an existing single machine and secondary machine (Windows and macOS).