The Express Server 9.5 installer can upgrade installations of Express Server 9.0 and later directly. You do not need to uninstall version 9; just start the version 9.5 installer and it will upgrade your existing installation.
Express Server 9.5 requires a new license, even for upgrade installations. You can obtain a new license by contacting LizardTech support.
The installer for Express Server 9 and later includes an automated upgrade process for upgrading from Express Server 8.
To upgrade from versions of Express Server prior to version 8, you must uninstall the previous version of Express Server, run the installer, and re-create your image catalogs in the Express Server Manager. You may want to save your license and configuration files for reference.