Renewing your Trend Micro program means purchasing another year or 2 of your protection coverage.
It is done per license or serial number which extends the expiry date or the period in which the program is active. This retains your existing serial number. However, if you purchased from a retail store or were provided with a new serial number from your online purchase, you need to replace the serial number on your program with the new one.
A new serial number means a new subscription.
The devices that have the same serial number you renewed will also extend its protection and share the same expiry date.
No other changes is made to your program when you renew your subscription.