I would like to find out whether license renewal can only be done after the license expired?

Can the user do a early renewal?

Yes, he can.

Hello Ilya,

Thank you for the reply.

I am thinking of doing it as the US currency is pretty weak at the moment, I will save quite a bit when converting to my local currency. :)

After paying for the renewal, how is the existing license prolonged? With another new license key?

I'll generate from your original key expirition time. And yes, you may replace.