This feature is available in the latest version of Upsales Subscriptions. Contact support@upsales.com to get upgraded for free.
When you win a opportunity and update an existing subscription, you need to create a prorated order.
This means the change in the subscription must be positive (an upsell).
To make changes beyond the upsell that result in a negative amount:
- Save the subscription with the upsell
- Open the subscription
- Edit the subscription amount