Postmark has introduced fully modular webhooks, allowing users to choose which events they want to send to each specified URL and add up to 10 URLs for different events. This change enables more powerful use cases, such as sending Open and Click events to the same URL. The new feature also includes separate Spam Complaint events, HTTP auth fields in the UI, custom HTTP headers, and a new tab on the Settings page for managing webhooks. Existing webhooks will continue to work as before, but users may need to update their existing webhooks to take advantage of the new modular functionality.