If you have customized the plugin slightly, e.g. changed css a little or made some slight code change, you can update BUT before that please make backup to save the changes you have. If you customized the plugin via child plugin, you can make update rigth away.
If you ordered customization service and our team made custom work, you can update without any issues if you have version 3.0 and higher. We do customization in the child plugin and i doesn't intefere with the core plugin.