Blesta Project Management is a plugin from the SystemFreaks suite. The optional Projects order module sells projects as services. Both are encoded and licensed through the SystemFreaks Update Checker.
Without the Update Checker: download the packages from your SystemFreaks client area, upload the blestacrm_project_management folder to plugins/ and the projects folder to components/modules/, then install them under Settings > Company > Plugins and Modules > Available.
Open Tools > SystemFreaks Update Checker, click Check Now, then click Update next to the plugin and the module. The Update Checker keeps a backup of the old folder and runs the upgrade. Your projects and tasks stay in place.