Sorry guys, we do not offer discounts for updates. Our updates policy is good and user friendly by itself:
1) Updates are not expensive.
2) You decide either you wanna pay for them or not. You can use builds that you have access to without any recurring payments. You can skip 1-2 years and never buy any updates. And after that you have to buy standard 6-months price and you'll get the latest build + additional 6 months for all future releases.
3) New versions of program (ZennoPoster 1, 2, 3, ZennoPoster MP) count as updates. We worked almost 1,5 years on ZennoPoster MP's developement and all our clients got it for the price of updates (of for free if they had active subscribtion).