At this time, canceling a paid subscription to a publication can only be done on a web browser by following these steps:
1. Head to your Substack account Settings or https://substack.com/settings/subscriptions and view a list of your subscriptions.
2. Select the paid publication that they want to update.
3. Scroll to the Account Actions section and tap where it says "To cancel your paid subscription, click here".
4. Tap "Cancel Subscription" to complete the process.
Note: Your paid subscriber benefits will continue until the end of the subscription plan's billing cycle.