Is this a mandatory update for the masternode ?
What is the best way to make this kind of update without loosing the current position in the reward queue ?
hey Coin++, that's not any issue really. Just rebuild/reinstall the client on your VPS and make sure it is up and running. If you are fast enough to do the update your masternode remains in the payment queue for an hour before dropping off. So, in other words, you have an hour to upgrade before you need to issue a
masternode start command from the cold wallet again.

Ok, thank you for the reply.