Draytek Vigor2110 Series User Manual page 36

Later, if you need to extend the license valid time, you can also use the Service
Activation Wizard again to reach your goal by clicking the radio button of
Formal edition with license key and clicking Next.
Check the box of "I have read and accept the above.." and click Next. Follow the
on-screen instruction to install the formal edition of WCF license.
26
Vigor2110 Series User's Guide