for an update from PRTG 9 to PRTG 13 valid maintenance is necessary. You can check the same in the web interface of your installation on page Setup | System Status.
If you have any further questions regarding your maintenance or on how to prolong the same, please contact our Sales Team at [email protected].
Improtant information regarding the update can be found here and here.
Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.