Transfer license Module "Class of Service" from freepbx 13 to 16

I need Advice.

Now I use freepbx13 , and i have account sangoma with paid licence of plugin “Class of Service”.

Can i login with my account with paid license to freepbx16(test server) to activate class of service future for making tests???

Activation on old server freepbx13 not be lost?

That is not supported. You will need to deactivate the license on the old server and activate it on the new to be able to use it on the new server.

If something goes wrong with new freepbx16 test server with activated license, can I activate it again in old server freepbx13 ?

Yes, but depending on previous history, you may have to open a ticket to get another reset.
I recommend that you first test without Class of Service to confirm that everything else is working properly.

Like @Stewart1 yes but there is a limited amount of times you can move activation between different hardware before you need to reach out to customer support to grant you additional activation.

I’ve done it before and it doesn’t take long for them to do it but the system is in place to discourage you from doing this too often.

how much time i can transfer activation?

I believe you can reset the hardware ID on your deployment only twice before you need to reach out to customer service to do it for you.